Which of the following is responsible for the formation of block mountains?

Block mountains are created by faulting. Faulting is the process of breaking and displacement of rock layers due to tensional or compressional forces. When one block of rock is pushed upwards and another block is pushed downwards, a block mountain is formed. The uplifted block is called a horst and the lowered block is called a graben. As the blocks continue to move, they can create a series of parallel mountains and valleys known as horsts and grabens. This process is common in regions of tectonic activity such as the East African Rift Valley and the Rocky Mountains in the United States.