Which ongoing process causes the buildup of energy that is released at a later time when an earthquake occurs?
A. Tectonic plates near a fault continue to move even though the fault remains motionless,
B. Nuclear reactions in Earth's lower crust release electromagnetic waves.
C. Heat from Earth's core slowly melts the rocks found deep in Earth's crust.
D. Jagged edges along a fault generate friction between two moving tectonic plates.