The image below shows what occurs under Earth's surface in certain areas.

What does the model demonstrate?
A.
In the asthenosphere, circulating heat expands the thickness of the crust of each plate.
B.
Tectonic plates are pushed apart due to steam caused by heat circulation in the asthenosphere.
C.
Tectonic plates are pushed apart partly due to convection currents moving through the asthenosphere.
D.
In the asthenosphere, as heat circulates, plates are pushed upward causing seismic activity.