Answer: Option 'A' is correct.
Step-by-step explanation:
When a huge block of rock is pushed up at a normal fault, a fault block mountain is usually formed.
They are formed by the movement blocks large blocks of crustal when forces in the crust of Earth pull it apart.
Some parts are pushed upward whereas other collapse down.
This led to formation of fault block mountain.
Hence, Option 'A' is correct.