Final answer:
The maximum frequency that can be detected as an input signal is half the Nyquist frequency, since the Nyquist frequency is double the maximum detectable frequency to ensure proper sampling.
Step-by-step explanation:
The Nyquist frequency is a concept in signal processing which determines the maximum frequency component that can accurately be represented by a sampling system. According to Nyquist’s theorem, to prevent aliasing, a signal should be sampled at least at twice the rate of the highest frequency present in the signal. Therefore, the maximum frequency that can be detected as an input signal, also known as the Nyquist limit, is half the sampling frequency.
The correct answer to the student's question is B. Half the Nyquist frequency. This is because the Nyquist frequency itself is already double the maximum detectable frequency component to ensure accurate signal representation.