What happened in the development of sonar directly AFTER the discovery of deep-sea trenches and mid-ocean ridges helped formulate the theory of plate technics?

Question

A. Seabed 2030 produced a map of the entire ocean floor.
B. Sonar caused coral bleaching events.
C. The US Navy began using multibeam sonar.
D. Sonar was used in World War I.

Answer 1

C. The US Navy began using multibeam sonar.