Which type of landform develops at plate boundaries where one oceanic plate descends beneath another?
a. volcanic island arc
b. mountian ranges formed by a batholith
c. lava plateau
d. rift valley

The correct answer is A. volcanic island arc.

When a plate descends beneath another, on the place where that happens, under the pressure from the mantle layer, magma rises towards the surface where the subduction line is. It pushes the oceanic floor up and volcanic islands start to form.