Why Are Most Active Volcanoes Associated with Plate Tectonic Boundaries

Why are most active volcanoes associated with plate tectonic boundaries?

A) Plate tectonic boundaries are created by volcanism.
B) Spreading or sinking plates interact at plate boundaries with other materials to produce magma.
C) Earthquakes at plate boundaries bring large amounts of magma to the surface.
D) In reality, most volcanoes are in the plate interiors rather than at plate boundaries.