Answer: A. fault-block mountains
The theory of plate tectonics refers to the movement of the plates of the lithosphere. It involves the movement of both continental and oceanic plates. In the convergent plate tectonics the two plates slides towards each other. Volcanic mountains, thrust faulted mountains and folded mountains are the examples of convergent plate tectonics and they are formed when the two plates converge or meet at a common site.
Fault-block mountains are formed due to the movement of crustal plates, from a common origin. The force inside the crust of earth separate these plates apart. Some parts of the crust remain upwards and the other part collapse down.