In the diagram below, what is the property of the wave indicated by the letter A?

Diagram of wave. The highest point is labeled A. (A is at the top of the swiggly line)

Amplitude
Crest
Frequency
Trough

I ALREADY KNOW THE ANSWER CAUSE I TOOK THE EXAM IS IS (CREST) BUT THERE ISNT AN ANSWER TO IT ON THE APP SO IM JUST HELPING <3