Which of the following causes earth's plates to move continuously?

a. glacial s deposit

b. earths magnetic field

c. convection in earth's mantle

d. radiation in the earth's core

Convection currents within the Earth's mantle exert heat and pressure on the crust, causing the plates to shift or expand.

The correct answer to this item is letter "C. convection in earth's mantle". Convection currents move tectonic plates when the rising mantle creates heat inside. The radioactive decay of several substances is responsible for the creation of the convection currents.