Question

Which letter is the correct answer and why

Answer 1

Option C

Explanation:

Here,

[Taking 'A' = 'a']

`a \: = \: 4\pi {r}^(2)`

Then for 'r',

`= > 4\pi {r}^(2) = a`

`= > {r}^(2) = (a)/(4\pi)`

`= > r = \sqrt{(a)/(4\pi) }`

`= > r = (1)/(2)\sqrt{ (a)/(\pi) }`

Hence,

Option C is correct .