What does the term "Nyquist frequency" refer to?

A) The maximum frequency that can be sampled without distortion

B) The minimum frequency that can be processed

C) The frequency at which a signal is doubled

D) The frequency that separates the passband from the stopband

Answer: A) The maximum frequency that can be sampled without distortion

Explanation: The Nyquist frequency is defined as half of the sampling rate of a discrete signal, representing the highest frequency that can be accurately represented without aliasing.