Correct Answer - Option 2 : 17 years

According to the given information,

Let John's present age be "X".

8 years ago John's age was "X - 8".

After one year John's age will be "X + 1".

Here, after one year, he will be twice the age of his age 8 years ago.

So, X + 1 = 2(X - 8)

X + 1 = 2X - 16

Taking X right side,

2X - X = 1 + 16

X = 17

Hence, **John's present age is "17 years"**.