What results from the collision of tectonic plates at convergent boundaries?

The collision of tectonic plates at convergent boundaries leads to the formation of deep ocean trenches. This occurs when one tectonic plate is forced beneath another in a process known as subduction. The subducting plate bends and creates a trench in the ocean floor, which can be observed in locations like the Mariana Trench, the deepest part of the world's oceans.

This process also has implications for the geological activity in these regions; while volcanic activity can occur in conjunction with the formation of trenches, the primary characteristic of convergent boundaries is indeed the creation of these deep trenches. The geological forces at play here also contribute to the formation of mountain ranges when continental plates collide, but the defining feature of convergent boundaries in oceanic contexts is the trench formation.

The other options, such as volcanic activity alone or the creation of new oceanic crust, do not directly represent the primary outcome of plate collisions at convergent boundaries, while formation of rift valleys is more characteristic of divergent boundaries, where plates are moving apart rather than colliding.