Why Does Oceanic Lithosphere Almost Always Sink Beneath Continental Lithosphere

Why does oceanic lithosphere almost always sink beneath continental lithosphere at convergent plate boundaries?

A) Oceanic lithosphere moves so slowly that it can only sink.
B) Oceanic lithosphere is at the bottom of the ocean, so it can't float high enough to ride over a continent.
C) Oceanic lithosphere is almost twice as dense as the underlying mantle.
D) Oceanic lithosphere is denser than continental lithosphere.
E) Oceanic lithosphere is partly liquid, so it floats on the solid continental lithosphere.