The answer is D - Faulting of rock in the Earths crust.
Explanation:
A fault is a planar fracture/discontinuity in a volume of rock in which there has been significant displacement as a result of rock mass movements.
Large faults within the earths crust result from the action of tectonic forces with the largest forming boundaries between the plates. Examples of this are subduction zones - (the lithosphere slides under the earths crust) or transform faults - (a fault which the motion is mainly horizontal.
In conclusion, the energy released from the continued movement of an active fault is the main reason for many of your major earthquakes.
