Final answer:
a. Sections of Earth's crust, known as plates, drift across Earth's surface due to currents generated deep within Earth's mantle.
Step-by-step explanation:
The statement that is true about plate tectonics is A. Sections of Earth's crust, known as plates, drift across Earth's surface due to currents generated deep within Earth's mantle.
Plate tectonics is a theory that explains how slow motions within the mantle of Earth move large segments of the crust, resulting in a gradual "drifting" of the continents as well as the formation of mountains and other large-scale geological features. This movement of the plates is driven by convection currents in the mantle, which transport heat from the interior to the surface, and cause the plates to shift and interact with each other.