Question

look at the image below. which letter represents the trough of the wave?
a
b
c
d

Explanation:

A wave trough is the lowest point of a wave, located below the wave's resting (equilibrium) line. In the diagram, label D points to this lowest, downward-curving section of the wave. By contrast, A is wavelength, B is the crest (highest point), and C is wave height.

Answer:

D