Question

which of the following describes how and where a trench forms in a plate tectonic setting?
a. a trench results from subduction and forms in the volcanic arc on the overriding plate.

b. a trench results from rifting and forms outside the rift on whichever plate is higher in elevation.

c. a trench results from subduction and forms on the ocean floor where the two plates meet.

d. a trench results from rifting and forms outside the rift on whichever plate is lower in elevation.

Explanation:

Trenches form at convergent plate boundaries via subduction—when a denser oceanic plate sinks under another plate. They occur on the ocean floor where the plates meet, not at rifts (which form divergent boundaries) or volcanic arcs (which are on the overriding plate).

Answer:

C. A trench results from subduction and forms on the ocean floor where the two plates meet.