Let's cut to the chase and analyse UPSC Prelims 2020. My intent is to not only provide a comprehensive analysis, but also to provide a broad framework for approaching such an analysis by yourself in future.

Before we begin, let me lay down the ground rules and things I intend to cover so as to make this an aspirant charter of sorts. I'll try to cover the following while discussing the questions:

1. Most reasonable approach that could have brought us to the answer( But not an absurd one that does bring us to an answer but is pretty ad-hoc and could not be emulated) : Dw, I'll bring out the diff bw the two as and how we encounter a question which enables us to appreciate the difference.

2. Peripheral things that we need to read up on in order to be prepped for potential offshoot questions on that topic again.

3. Role of Serendipity factor(I also like to call it Slumdog millionaire factor for reasons that'll be clear soon).

4. My actual approach in the exam hall and what were my personal takeaways for improving the use of elimination tactics.

5. Use of certain factoids for Mains Value Addition.

A General Note on Elimination Heuristics:

1. Extent of using them would foremost depend on your risk appetite. My risk appetite tbh is limitless rn. I've come to attempt as many questions I possibly can, without of course taking a blind guess.

2. Good starting point (https://mrunal.org/gm) :These can be useful if you know how and when to apply them. Always keep an open mind and tinker with the possibility, atleast during mocks or while analysing the questions at home.

3.Elimination is not a science. Know that the theory of probability works only when the sample size of questions is large enough. In exam, you can have localised anomalies where all your 50-50s turn out to be incorrect consecutively.

Which brings me to my initial assessment of Prelims. It's a game of odds. There's no guarantee. But if you do your basic books really well, know your way around the elimination heuristics and have analysed PYQs since 2013 thoroughly, you have a high 'possibility' of clearing it. I think this has been a sufficing warmup. Let's jump on the Main course!

Offical QP and the answer key

This is an interesting question. Interesting because UPSC has deliberately framed statements that are usually incorrect. i.e. 'Negative statements'(use of 'cannot')and 'Statements about mandates'. UPSC decides to up the game.
In addition to that, a bunch of different heuristics could be applied in this question.
In #1, a data point is given and UPSC is known to tinker with data.
In #2, a slightly extreme statement is given 'cannot enter into any contract'.
In #3, the mandate would be against financial inclusion as Aadhar is not mandatory anyway, and govt is pushing for financial inclusion.
And in #4, CFI is under parliamentary control thus can have the requirement of more due diligence.

So in order to get this question correct, not only do you have to apply a 'nuanced' guesswork, but also have to be lucky in the sense that which elimination heuristic you prefer over the other. For instance, I got this question incorrect as I eliminated '2' given that it appeared extreme. I further chose 'c' over 'a' as likelihood of a single statement to be correct is more than the likelihood of two statements to be correct.

The way to get this correct could have been to eliminate '1' considering UPSC 'usually' tinkers with data. And then selecting 'b' over 'c' by eliminating '3' using the financial inclusion conjecture.

What did I Iearn from this ques tbh? If there are multiple heuristics applicable in a question with differing potential answers, and you have little to no knowledge on the topic, the question is better left un-attempted.