Which feature is associated with tectonic plate boundaries and significant geological activity?

The feature associated with tectonic plate boundaries and significant geological activity is oceanic trenches. Oceanic trenches are deep, narrow depressions in the ocean floor formed by the subduction of one tectonic plate beneath another. This process is a major aspect of tectonic activity, as it is involved in the recycling of the earth's crust and is often linked to volcanic activity and earthquakes.

Folding mountains, while also a result of tectonic activity, occur primarily at convergent plate boundaries where two continental plates collide, causing the earth's crust to fold and form mountain ranges. Fault lines represent fractures or zones of weakness in the earth where tectonic plates have moved, commonly associated with earthquakes. Alluvial plains, on the other hand, are flat lands formed by the deposition of sediment from rivers and are not directly related to tectonic plate activity.

Therefore, among the provided choices, oceanic trenches are the most significant feature directly tied to tectonic plate boundaries and geological processes.