Answer:
Trough
Step-by-step explanation:
There are several quantities of a wave that are indicated in the figure:
A) This is the point of maximum positive displacement of the wave --> this is called crest
B) This is the value of the maximum displacement of the wave measured with respect to the equilibrium position of the wave --> this is called amplitude
C) This is the point of maximum negative displacement of the wave --> this is called trough
D) This is the distance between two consecutive crests (or between two consecutive troughs) of the wave --> this is called wavelength