**If $$ \\sqrt{10-2\\sqrt{21}} $$ $$ \\sqrt{8 2\\sqrt{15}} $$ $$ =\\sqrt a \\sqrt b $$ , where a and b are positive integers, then the value of $$ \\sqrt{ab} $$ is closest to :** A) 4.6 B) 5.9 C) 6.8 D) 7.2 Click Link for Answer