Correct Answer - A
Potential energy is minimum (in this case zero) at mean position `(x = 0)` and maximum at extreme positions `(x = + A)`.
At time `t = o`, `x = A`. Hence, `PE` should be maximum. Therefore, graph `I` is correct. Furhter in graph III, `PE` is minimum at `x = 0`. Hence, this is also correct.