Trenches occur at divergent plate boundaries.
a. true
b. false

b. False

Explanation:

The trenches are not physical features that occur on places where there are subduction zones between the tectonic plates, but they do not appear on places where there are divergent plate boundaries. The trenches are simply very deep, narrow, ocean beds, that have very steep sides.

The divergent boundaries are the opposite boundaries from where the trenches occur. These boundaries occur between tectonic plates that move away from each other. The typical physical feature at this type of plate boundaries are the mid-ocean ridges (if it occurs in an ocean), or the rift valleys (if it occurs on land).

This type of boundary produces new crust on Earth, and they also can split a tectonic plate into two separate plates, or even give rise to a new continent.