The answer would be:
B. Oceanic plates are made of dense rock; therefore they sink into the asthenosphere more readily. Continental plates are made of lighter, more buoyant rock.
Her is more about your question:
In a convergent boundary plates collide or move towards each other. What happens between an oceanic plate and a continental plate that collides is that one would subduct beneath the other.
Oceanic plates are a lot thinner than continental plates and they are a lot more dense. Because continental plates are much thicker and less dense, they force the oceanic plates under. This process is called subduction.
