Which of the the following best describes the frequency of a wave?
A. It is the measure of the distance from one crest of the wave to the next crest of the wave.
B. It is the measure of the distance between the crest or the trough of a wave and its rest position.
C. It is the measure of the distance a single wave travels in a given period of time.
D. It is the measure of how many times a wave cycles in a given period of time.