For the below question, square root can be either positive or negative, it means A can be greater or lesser than B. How the answer is ‘C’?

underoot (x^4+6x^2+9) = (x^4+6x^2+9)^1/2 —> 1

Now,

x^4 + 6x^2 + 9 = (x^2+3)^2 --------> 2

Combining results of Eq 1 and 2

((x^2+3)^2)^1/2 ----> the inner whole square gets cancelled out and we are left with x^2 +3

we are using the radical rule x√(n)^x = n given n >0