Which of the following is characteristic of collisional coastlines? Low lying coastal plain with barrier islands
Large rivers and deltas
Tall mountains onshore, submarie canyons offshore
Broad estuaries

Tall mountains onshore, submarine canyons offshore.

Explanation:

Collisional coastlines are the ones that are found at locations where tectonic plates collide with each other or rather have a convergent plate boundary. This causes one of the plates, the lower-lying and denser one to subduct below the higher positioned and less dense one. This results in the formation of mountains and ocean trenches.

Onshore, there are high mountains, and the reason for this is that when one of the plates moves below the other, the crust along the coastline lifts up. Offshore though, it is a contrasting picture, and when the subduction zone is there are submarine canyons, known as ocean trenches, and they are the deepest parts in the oceans on Earth.