Answer: A. fault blocks
Explanation: Fault-block Mountains - Fault-block mountains are formed along fault lines (the edge between plates).
The huge chunks of rock on either side of the fault are called fault blocks. As the tectonic plates
move, some of the fault blocks are pushed up, while others are pushed down. This difference in
elevation (height) forms fault block mountains. The Sierra Nevada Mountains in the western United
States are fault-block mountains.