Question

what geological processes are responsible for the formation of volcanoes at subduction zones?
a convection currents in the mantle
b tectonic plates moving toward each other
c transform boundaries between tectonic plates
d magma upwelling from the mantle

Explanation:

At subduction zones, one tectonic plate moves beneath another. As the denser plate subducts, it heats up and releases water and other volatiles into the overlying mantle wedge. This lowers the melting - point of the mantle material, causing it to melt and form magma. The magma then rises to the surface to form volcanoes. Tectonic plates moving toward each other is the key process that initiates the subduction and subsequent volcanic activity. Convection currents in the mantle are a general process but not the direct cause at subduction zones for volcanic formation. Transform boundaries are associated with lateral plate movement and not with subduction - zone volcanism. Magma upwelling from the mantle is a result of the subduction - related processes rather than the initial cause.

Answer:

B. tectonic plates moving toward each other