If a deep-ocean trench is located adjacent to a continent, active volcanoes would likely be found

The answer is Landward from the trench. Such mountain ranges are formed at convergent boundaries as two tectonic plates, moving in opposite directions, collide. As the oceanic plate is subducted, since its denser, it begins to melt to form magma. The magma rises and erupts to form the mountain ranges landwards on the overlying continental tectonic plate. A trench is characteristic of a subduction zone but cannot be offshore but rather onshore in the deep trench of the oceans.