Answer:
Choice A is the answer.
Explanation:
We have given an expression.

We have to find the value of x.
We use following formula to solve this:

Applying above formula , we have


Eliminating fraction, we have
4 = √x
Taking square root to both sides of above equation, we have
(4)² = (√x)²
16 = x
x = 16 which is the answer.