For the successful reconstruction of signals :
(a) Sampling frequency must be equal to the message signal
(b) Sampling frequency must be greater to the message signal
(c) Sampling frequency must be less to the message signal
(d) Sampling frequency must be greater than or equal to the message signal
I had been asked this question by my school teacher while I was bunking the class.
Question is from Signal Reconstruction in section Digital Control Systems of Control Systems