which term defines the distance from crest to crest, or from trough to trough?\n speed\n period\n…

Brief Explanations:

In wave - related concepts, wavelength is defined as the distance between two consecutive crests or two consecutive troughs. Speed is the rate of wave propagation, period is the time taken for one complete wave cycle, and frequency is the number of wave cycles per unit time.

Answer:

C. wavelength