How frequently must an analog signal be sampled to be accurately reproduced?

This principle is known as the Nyquist-Shannon sampling theorem. It states that to perfectly reconstruct an analog signal from discrete digital samples, the sampling frequency must be at least twice the highest frequency contained in the signal. If a signal is sampled at less than this rate, a phenomenon called "aliasing" occurs. Aliasing causes high-frequency components to mathematically fold back into the lower frequency spectrum, creating distortion that makes accurate signal reproduction impossible. Options suggesting half the rate or the exact same rate would result in a complete loss of the original waveform's information, while sampling at four times the rate is unnecessarily higher than the theoretical minimum required.