Which theory of plate movement relies on the weight of the subducting crust?
a. slab pull
b. slab push
c. hot plumes
d. mantle convection

Slab pull is the theory of plate movement which relies on the weight of the subducting crust.

Explanation:

Plate movement are the measure of motion of tectonic plates. As it is known that our earth crust is composed of different sizes of tectonic plates. So these plates can move depending upon the pressure exerting on it. So slab pull is one of the theories existing with plate movement. In this case, the movement of the plates occur due to the weight of the subducting crust. The subducting crust is the boundary between tectonic plates. So depending upon their weights, the slab pull theory works.