Answer:
b) T remains the same and V_max doubles.
Step-by-step explanation:
As we know that the time period of oscillation is given as

so it is independent of the amplitude of oscillation
So if we increase the amplitude then it will not change the time period of the oscillation
Now the maximum speed of the oscillation is given as

now if we increase the amplitude then maximum speed will also increase
so correct answer will be
b) T remains the same and V_max doubles.