Which event is the most common at oceanic-oceanic convergent boundaries?

a.
island arcs

b.
rift valleys

c.
earthquakes

d.
volcanic mountain ranges

Option (A)

Explanation:

In a convergent plate boundary, two plates move towards each other. When two oceanic plates move against one another, it results in the formation of a subduction zone, where the denser oceanic plate subducts below the lighter oceanic plate. This zone is marked by the creation of a trench above it. This trench is usually a narrow V-shaped depression. As the heavier plate goes down, it undergoes partial melting, that melts the rock and mixes up with the uprising magma. This eventually rises up due to the force exerted by the convection current and forms island arcs in the over-riding plate.

Thus, the correct answer is option (A).