Answer:
A. Crest
Explanation:
Longitudinal wave is a type of wave that is characterized by the particles of the medium's movement in a parallel direction in comparison to the direction in which wave travels, such that, in compression of longitudinal wave, the density of the wave medium is at its highest due to its closeness together than natural state, while in rarefaction, the density is at its lowest due to wave medium spread apart than normal.
Similarly, in Transverse wave, the crest of a wave implies the medium has reached the highest point while the trough of the wave depicts the lowest point the wave medium has reached.
Therefore, longitudinal wave's compression and rarefaction equates accordingly to the crest and trough of a transverse wave.
Hence, a compression of a longitudinal wave is like a CREST of a transverse wave.
