One of the driving forces of plate motion is: A. volcanic eruptions along coastlines B. meteor impacts in the ocean basins C. convection currents in the mantle D. hot liquid magma in the inner core

C

Explanation:

- Convection in the Mantle (heat driven) : is the very slow creeping motion of Earth's solid silicate mantle caused by convection currents carrying heat from the interior to the planet's surface.

- The mantle is heated from within, cooled from above and cools off with time (secular cooling). All of these effects drive convective motions.

- The distribution of radioactive elements within the Earth is not uniform. Heating from below is minor, at least for the mantle as a whole. Viscosity varies with depth and temperature. Solid-solid phase changes (some exothermic and some endothermic), occur at various depths. Rheology changes with stress.