Consider a signal xt whose highest frequency is 100 Hz What

Consider a signal x(t) whose highest frequency is 100 Hz. What is the Nyquist frequency? Consider the below three cases where the signal is sampled at
(a) 100 Hz
(b) 250 Hz
(c) 500 Hz
Under which case(s) would there be aliasing problem. Explain it.

Option A

And aliasing can be find by using Fourier spectrum if the given frequency is 100hz then aliasing occurs at 99 or 101