Answer:
Option (a)
Step-by-step explanation:
In a convergent plate motion, two plates move towards each other and the denser plate gets subducted beneath the less dense plate.
So when an oceanic plate collides with a continental plate, the oceanic plate gets subducted below the continental plate. It is because the oceanic plate is denser than the continental plate. The oceanic crust is comprised of the rock of lavas and basalts that contains mostly pyroxenes and plagioclase feldspar and they are comparatively denser, whereas the continental crust is comprised of granite and silicate rocks that are comparatively less dense.
This is why the oceanic plate sinks below the continental plate.
Thus, the correct answer is option (a).