Question

From which ocean floor destination would a sonar signal take the longest amount of time to return to the receiver?

A.
a continental shelf

B.
a trench

C.
a deep-ocean basin

D.
an abyssal plain

Answer 1

B. a trench

A sonar return time depends on the distance to the seafloor. Ocean trenches are the deepest features (e.g., Mariana Trench), so a ping from there travels the farthest and takes the longest to return.