For people who read IMF thoroughly, this was a a direct question.
But there still are ways to get to the right answer with logical guesswork even if one hasn't thoroughly prepped IMF. So two heuristics aid our cause in this question.

Heu#1: Taken from Q#5 , a more specific option is more likely to be correct than a vaguely worded one. And 'b' is as vague an option as it possibly gets.

Heu#2: Usually if two statements are similarly worded with only slight variation, it's very likely that the answer is one of them.
For instance, option 'c' and option 'd' are similarly worded but for the orgs that are mentioned. Additionally, WTO is a facilitator while IMF has a more hands on functioning operating with credit systems. So even if I were not exactly aware of the answer, I would have still marked 'd'.

Another takeaway is to prepare atleast these 3 orgs, i.e. WB, IMF and WTO really thoroughly. Each year or every alternate year, there's atleast one question from one of these 3 organisations.

How many times will I repeat it? Idk, as many times as the need be. First 51 articles of Consti, Preamble and the chapter on legislature needs to be internalised. No excuses on that.

Moreover, to know that '3' is correct doesn't even need too deep an understanding of DPSPs.
That leaves us with 'c' and 'd'. After that, it's a matter of how well you've read the chapter and could back your knowledge in the exam hall.
Though at the outset, statement '2' is tempting as it appears to be an extreme statement, but is correct nonetheless.

Thus, conviction is key in the exam hall. And 'blind' adherence to any rule or heuristic is a sin.

Statement '1' was peculiar so I had to leverage my peripheral knowledge while also backing my convictions.

We know that a person after attaining the age of 18 becomes eligible to vote. Whereas to become a member of legislature, minimum age requirement is 25, after which one become eligible to serve at a ministerial post.
Even if one were to be made a minister without getting a membership of the house, it sounded unlikely that an 18 yr old Voter ID holder could be made a minister. for 6 months. So I eliminated '1'.

For statement '2', I couldn't remember any provision for permanent disqualification. The disqualification from my understanding was contemporaneous to the duration of the punishment plus some additional time on top of it. Moreover, 'data' points are more often than not manipulated by UPSC in questions. Thus, the sentence term of 5 years seemed sketchy. So I marked 'd' which eventually turned out to be the correct answer.

My take on these questions is fairly straightforward. It's difficult to memorise and recall such minute details.
If you could use common sense with your peripheral knowledge, you would have every shot of getting these questions correct with practice.

Note how we have another question from Parliament.

Two ways to arrive at a 50-50 chance.
Either you know '1' to be correct which is a straightforward fact from the chapter. Or you know that '2' is incorrect as there's no mandate on conducting a certain number of sessions.

Either way leaves you with 'a' and 'c'.
Now I knew that the gap between two sessions could at max be 6 months. So a logical extrapolation suggested that it there's a requirement of atleast 'two' sittings of Parliament over an year. I went ahead and marked 'a'.

UPSC key had 'c' as an answer which gave me a reasonable takeaway. In questions on polity, it's always better to take the statement on its face value and avoid extrapolations. Since the parliament 'explicitly' doesn't suggest a requirement of a minimum no. of sessions, so '3' made more sense from that argument.

Hey guys! Accept my apologies for not being able to finish this discussion. In between now and the last time I was here, life happened. Couldn't clear Mains 2021 and had to revaluate my future course of action. Also, as I believe, there's no point in reinventing the wheel. By the stroke of serendipity though, I got a document which might help you before pre. Make good use of it.

Hopefully if luck obliges, I'll be back soon. Best wishes meanwhile.

Some answers given by the author are incorrect. So always use the official answer key to validate.

Q20. Official answer is 'A' not 'D'
Q42. Cancelled by UPSC
Q51. Official answer is 'C' not 'D'
Q58. Official answer is 'A' not 'D'
Q77. Cancelled by UPSC
Q83. Official answer is 'D' not 'B'
Q89. Official answer is 'D' not 'A'
Q91. Official answer is 'B' not 'C'

Find the solution of Prelims UPSC 2021. Use this solution as a tool to use heuristics more smartly. Also, now you would see why this paper was really uncertain given so many random questions and nearly 11-12 contentious questions whose solution could only be confirmed by the honorable commission.

Q1. No provision in constitution regarding RBI as it is a statutory body, eliminate '2' arrive at the answer.

Q2. Answer either 'b' or 'd'. Based on my experience, I try to negate statements with simple examples and if I cannot, I assume the statement to be correct. I can negate '1' by thinking of a casual 'labour' who is not given EPF. I negate '1' and mark 'b'.(Wait for UPSC's key to confirm)

Q3. Static, counter cyclical fiscal policy. 'b'

Q4. Word association. 'Inferior' good's demand increasing with increasing income of consumer highly unlikely. Eliminate '3' and arrive at 'a'.

Q5. Static. '1' is factually wrong, arrive at 'b'.

Q6. 'Influence' is a soft, broad term. I prefer to mark 'All' i.e. 'd'.

Q7. 'deposit' can't be an 'investment'. Furthermore, FII with 'certain conditions' is generic and likely to be correct. 'a'.

Q8. 'Necessarily'.'1' is certain while '3' is only 'likely' thus 'a'.

Q9. Occam's razor i.e. Black money=Tax evaded money. 'd'.

Q10. Repeated question(2013), 'd'.

Q11. Repeated question(2019), 'c'.

Q12. 'high interest rates'= less easy to procure funds. Eliminate '5' and arrive at 'a'.

Q13. 'Organisation combination' usually mismatched(BSE+RBI looked incoherent combination; BSE's collab with SEBI would have made more sense). '2' is generic. 'b'.

Q14.'Organisation combination' usually mismatched. Eliminate '2' arrive at 'c'.

Q15. Static, 'b'.

Q16. 'Word association'; 'R2', 'a' has 'responsible, recycling'

Q17. Answer either 'b' or 'd'. Wait for UPSC's key.

Q18. 'Generic statements, can't negate any strongly. 'd'

Q19. 'Word association'; 'Blue=Water related', 'a'.

Q20. Static, 'c'.

Q21. Random trivia, 'c'.

Q22. 'Cyanobacteria= Blue green algae'; 'Diatoms also primary producer' These options have already featured in PYQs. So better to google PYQ options. Also in copepods, 'pod' means legs, thus likely to be an animal than a 'primary producer'. 'b'

Q23. '3' is well known. For those who watched cartoon series 'Sonic the hedgehog' series would know '1' is also correct. Otherwise can take a guess between 'c' and 'd'. Answer='d'.

Q24. Eliminate '3'(legally binding not usually correct),'4' is generic thus can't be negated strongly, 'a'.

Q25. Answer either 'b' or 'd'. Wait for official answer key.

Q26. Random trivia, 'c'.

Q27. Static, 'c'.

Q28. 'Spot the odd one out'. Seahorse doesn't seem to be a detrivore. Eliminate and arrive at 'c'.

Q29. Random trivia, 'a'.

Q30. Unless you have legitimate reason to negate an option, I would assume it to be correct. Couldn't negate either, so 'd'.

Q31. Eliminate '2'(only temple, less likely), arrive at 'c'.

Q32. Static+ Also in news due to recent UNESCO inclusion, 'a'.

Q33. Took a calculated risk. Period being asked is narrow(1600-1625), usually empires don't expand too much in the early phase within short periods. Started off at 'Surat', 'Broach' sounded Gujarati city and less likely that could have also expanded to 'Chicacole' which didn't 'seem' to be a Gujarati city by its name. 'a'.

Q34. Two hints given, 'Post Gupta' and 'Northern'. 'Yadavas were southern, thus eliminate '5'. 'Guptas' of Magadha sounded like an offshoot kingdom. 'b'

Q35. Unless you have legitimate reason to negate an option, I would assume it to be correct. Though 'Wrestling' was odd, no option which had '2,3, and 4'. Backed my hunch and marked 'd'.

Q36. 'Related options, answer one of those two'. 'a' about 'National Flag', 'c' about 'National Anthem'. Then it would be a 50-50 guess. Answer is 'c'.

Q37. 'Burzhaom' in Kashmir, less likely to have a geology for rock cut shrines(mostly found in deccan). Couldn't negate either 2 or 3. 'd'

Q38. 'Taimur' ended Tughluq reign and Sayyid dynasty's rule started after that. But Md. Bin tughlaq was not the last ruler of the tughlaq dynsaty. Eliminate '2'. '1' was a static well known fact. 'a'.

Q39. 'Random trivia', all statements filled with red flags. Answer to be confirmed by UPSC's key.

Q40. Similar to Q39. Answer is 'b'.

Q41. Another random trivia question. Answer is 'b'.

Q42. Static, 'b'.

Q43. Static, 'a'.

Q44. Not so well known publication. Answer is 'c'.

Q45. Static, 'a'. Also in these 'ordering' questions, UPSC usually gives both ascending and descending order in the options to confuse. Only 'a' and 'c' are diametrically opposite, so even if you're not sure about the question, answer likely to be one of 'a' or 'c'.

Q46. Static, 'c'.

Q47. Static, 'd'.

Q48. Static, 'a'.

Q49. Static, 'a'. Prepare these oft repeated caves in detail.

Q50. 'Organisation mismatch' likely. UNICEF given instead of UNESCO. 'b'

Q51. No kind of farming could be easy in 'semi arid regions'. Rest the three statements are generic. 'b'.

Q52. '1' is Factual, '2 and 3' are generic, 'b'.

Q53. UPSC's key will confirm the answer. 'a'(More likely) or 'd'.

Q54. Word association, 'Didwana', 'Khatu'(similar to Khatu Shyam shrine) sound Rajasthani places. 'd'.

Q55. Static, 'b'.

Q56. '1' is factual and usually is well known that ISA(Intl. Seabed Authority) grants licenses.'2' and '3' generic. Arrive at 'b'.

Q57. Static, Sugarcane is water intensive. 'a'.

Q58. Static conceptual, 'c'.

Q59. 'Random trivia', all statements filled with red flags. Took a risk by selecting 'all' as couldn't strongly negate either, which paid off . 'd'.

Q60. 'Occam's Razor- simplest answer is usually the correct one', Fast decomposition hinted towards high temp and moisture. Plus epiphytes = Tropical rain forest. 'd'.

Q61. '2' and '4' correct from Static. 'c'.

Q62. Static, 'b'.

Q63. '5' is generic. No option with 'ALL' so atleast one or more than one statements incorrect. Factual statements usually have a possibility of being incorrect. '1' has two facts 'leguminous' and 'evergreen'. Arrive at 'b'.

Q64. Static, 'b'.

Q65. Both '1' and '2' generic, can't be strongly negated. 'c'.

Q66. This has been in news since 3-4 years. Though still a contentious question, in my understanding, answer is 'b'. '1' is factually incorrect as you need therapy before the fertilisation. '2' is correct as mitochondrial diseases inherited from the mother. Still can wait and confirm from UPSC's official key.

Q67. 'Two similar looking options', 'a' and 'b' about 'crop plants'. GM more famous than cloning usually, arrive at 'b'.

Q68. Contentious, was a UP-PCS PYQ and answer given was 'c' while some claim the answer should be 'd'. Let's wait for the official key.

Q69. Contentious, as back in 2013/2014, UPSC gave 'a' as an answer to a similar question but now, 'all' can be synthetically cultured. So 'a' or 'd' based on UPSC's key.

Q70. Difficult factual question. '2' can be validated as 'AIDS' therapy is called 'ART=Anti retroviral therapy' so '2' makes sense. But '1' is factual. Answer is 'b'.

Q71. Static, 'a'.

Q72. Eliminate '2', as LED's have longer life spans. logically, '1' also made sense as LED's are more efficient than Lamps and lack of 360 degree coverage is coherent with high efficiency. 'c'.

Q73. Covid related, much in news. 'd'.

Q74. Random trivia. But if desperate to attempt, can think of how 'low density' plastics are more harmful in general(realted to ban of single use plastics). 'a'.

Q75. Random trivia. 'd'

Q76. Static, 'd'.

Q77. Static, 'c'.

Q78. Random trivia. Claims for right answer range from 'c' to 'd'. Wait for the official key.

Q79. Static, 'c'

Q80. Static, '3' is wrong, '1' is wrong too, Arrive at 'b'.

Q81. Random, contentious question. In my understanding, statement '1' is generic, and '2' is also welfare oriented. Likely answer, 'c', but wait for the official answer key.

Q82. Word association, 'judicial custody'= under court(i.e. jail) not police station. '2' is logically coherent. 'b'.

Q83. 'Parole' not a matter of right. '2' is correct. 'b'.

Q84. Static, 'd'.

Q85. Static, 'a'.

Q86. Contentious, either 'a' or 'b'. Wait for the official answer key.

Q87. Contentious, either 'a' or 'b'. My understanding is, it should be 'b' as usually more defined and verbose statement is correct. But anyway, let's wait for UPSC's answer key.

Q88. Static, 'c'.

Q89. Static, 'a'.

Q90. Static, 'd'.

Q91. Static, 'b'.

Q92. Contentious between 'a' and 'b'. Let's wait for UPSC's official answer key.

Q93. Static, 'b'.

Q94. Static, repeated from 2020, 'd'.

Q95. 'Ho' tribe usually well known, 'd'.

Q96. Static, '1' is factually wrong, '2' has two data points(1954, suspended only once) thus high chances of being wrong, '3' also has a data point(restricted to '5'). 'd'.

Q97. 'Organisation combination' usually mismatched by UPSC, Eliminate '1' and arrive at 'd'.

Q98. Random trivia, difficult to eliminate. 'c'.

Q99. Random trivia, difficult to eliminate or validate either. 'b'.

Q100. Random trivia. 'd'

Finally delivering on my initial word, made 3 months back. This brief solution I believe is much more effective than the elaborate one. Find the solution of Prelims UPSC 2020. Know that applying heuristics without any knowledge or context is a cardinal sin. But heuristics when combined with a solid edifice can bring unparalleled rewards. I'm certain you would have worked on the edifice, so find the gift of applying heuristics!

Q1. No option without both '3' and '4'. So one of them is correct. Since CFI has legislative oversight, more likely to have Aadhar mandate. Also, govt aiming for financial inclusion, so '3' also less likely. Eliminates 'c' and 'd'. UPSC known to tinker with data, so 'b' most likely.

Q2. Static, 'b'.

Q3. '1', '2' basic static pointers. '3' has two facts- 'yearly sanction' & 'no carry over', Data in '4' is reasonable '10%' and also coherent with govt's focus on audit & transparency. 'd'. Note that you shouldn't blindly follow any 'heuristic' eg. 'Data' is always wrong. Always use heuristics with context, keep practicing to improve. Blind blanket use of any heuristic is akin to a blind guess which is detrimental to one's chances.

Q4. Static, 'd'.

Q5. Static, 'b'.

Q6. Static, 'd'.

Q7. Static, 'd'.

Q8. Notice the directive in the question- 'reflects'. With a generic directive, a generic correlation could always be established bw the context(UDHR) and the options(Preamble, DPSP,FD). So 'All of the above' is more likely to be correct. 'd'.

Q9. Unless you have legitimate reason to negate an option, can assume it to be correct. Eliminate '4' ,because 'all' sounds extreme & govt ideally would not provide a free legal service to a rich industrialist just because he/she is a senior citizen now. To choose between '1' or '3', a quick calculation of monthly income gives us a choice bw a person with a monthly income of around 8k and a member of OBC community with a monthly income of 24k. The 3x(times) diff was too much even considering the need for affirmative action. 'a'.

Q10. '3' is well known, eliminate 'a' and 'b'. '4' looks illogical for two simple reasons.One, if the '2' in 'Under2' denoted the age of the 'kid', 'toddler rights' would have been a more apt context, than 'child' rights, which are usually given in the context of Under 18. Also, targets of Under 2 and Under 1.5 are related to Climate change. 'd'.

Q11. Static, 'b'.

Q12. Static, 'a'.

Q13. '1' is incorrect, well known fact. Logically statement '2' makes complete sense. Maybe the commission meant that 'judicial review' not written anywhere in consti. 'd'. You've to accept some collateral damage in a couple of questions where the key would go against common sources/understanding. Which again brings us to the initial assessment about prelims being an exam of odds than of certainties.

Q14. In such questions, one can focus on negating the premise of given options to arrive at the 'last option standing' than rushing to what one thinks is right, because such questions are also a matter of interpretation. Option 'c' was definitely wrong as Gandhiji spoke about trusteeship and not abolition of pvt property. In Option 'd', word association hinted towards a system where economics determine one's being. Can't directly relate it to any of Gandhiji's ideas. 'Class struggle'(Diff bw the ends of capitalist and labour class) also didnot make sense in context of Gandhian thinking as he always tried to bring diverse groups together for the common goal of independence. 'Stateless' society is the last option standing, plus 'gram swaraj' concept of 'Gandhiji' aligns well with it. 'a'.

Q15. Interpretation based question. Focus should be on finding the one option that is 'closest' to the context of the question than the others. Logically it is the parliament itself that has the power of widening its own scope. So I eliminated 'a'. Political stability is incumbent upon the political parties(by means of forming alliances) and their electoral performance. Bureaucrats ideally have little to no role in ensuring that. Moreover we read about political neutrality as being one of the cardinal values required in civil services. Eliminate 'c'. Option 'd' looked logically correct. Moreover it is more likelier to be correct than Option 'b' as public policy implementation is a part of the core job profile of a bureaucrat whereas strengthening federalism is an ancillary benefit of the services. 'd'.

Q16. Static, 'd'.

Q17. Well known fact. But there still are ways to get to the right answer with logical guesswork even if one hasn't thoroughly prepped IMF. A more specific option is more likely to be correct than a vaguely worded one. And 'b' is as vague an option as it possibly gets. Also, usually if two statements are similarly worded with only slight variation, it's very likely that the answer is one of them. Here, option 'c' and option 'd' are similarly worded but for the orgs that are mentioned. Additionally, WTO is a facilitator while IMF has a more hands on functioning operating with credit systems. 'd'.

Q18. Static, 'd'.

Q19. Unless you have legitimate reason to negate an option, can assume it to be correct. Age eligibility for voting=18. Age eligibility to become a member of state legislature=25, after which one becomes eligible to serve at a ministerial post. Thus, even if one were to be made a minister without getting a membership of the house, it sounded unlikely that an 18 yr old Voter ID holder could be made a minister. for 6 months. Eliminate '1'.
Statement '2' had two facts, '5 years' and 'permanent disqualification'. If either is wrong, statement would be wrong. So eliminated '2'. 'd'.

Q20. '1' is a straightforward fact and '2' is incorrect as there's no mandate on conducting a certain number of sessions. Either way leaves you with 'a' and 'c'. Now the gap between two sessions could at max be 6 months. So a logical extrapolation suggested that it there's a requirement of atleast 'two' sittings of Parliament over an year. But in questions on polity, it's always better to take the statement on its face value and avoid extrapolations.(Similar to Qn 13).Since the parliament 'explicitly' doesn't suggest a requirement of a minimum no. of sessions, so '3' made more sense from that argument. 'c'.

Q21. Static trivia. 'b'.

Q22. Factual. 'b'.

Q23. Static+ overall colonial rule's impact was negative. 'a'.

Q24. Tripartite struggle, thus Pala and Rashtrakutas would be contemporary. Also, foundation comes before rise. So '4' before '1'. Dravida architecture founded around Pallava age and reached zenith under Cholas. So '2' before '3'. 'c'.

Q25. Static, 'c'.

Q26. 'Sakharam' sounded like a 'Marathi' name. Logically, for him to use 'desh' specifically for 'Bengal' didn't make sense, 'a'.

Q27. 'Cancelled'

Q28. Less known journal, and we usually read about the imp works by Phule, Gandhi and Ambedkar. 'a'.

Q29. Usually if two statements are similarly worded with only slight variation, it's very likely that the answer is one of them. 'a' and 'c' about 'land'. 'Urban' classification less likely as urbanisation happened in phases and was not a continuous feature. Whereas, measurement of land would always be needed no matter what the era. 'a'.

Q30. 'Occam's Razor', religious tolerance related with 'Ashoka'. 'a'.

Q31. 'Word association', 'Paramitas' has 'Param' which means 'epitome', close to 'perfection'. 'c'.

Q32. '2' and '3' are coherent(conjugal rights and consent). '1' has no direct relation with either and looks to be the odd option out. 'b'.

Q33. Static, 'b'.

Q34. Static, 'd'.

Q35. Static, 'd'.

Q36. 'Amarsinha' in Gupta period is well known. 'c'.

Q37. Much in news since 3-4 years, 'd'.

Q38. Directive is 'present state', 'effectively'. '2' meaningful songs and stories seems unlikely due to the directives. 'b'.

Q39. Ideally, '4' should have been wrong. But factually, '2' is also wrong. As in Q13, you've to accept some collateral damage in a couple of questions where the key would go against common sources/understanding. 'c'.

Q40. Unless you have legitimate reason to negate an option, can assume it to be correct. '2' can be easily eliminated. 'd'.