Landforms that have been changed by people and why

Most landforms change very slowly over many, many years. New mountains have formed as the plates of Earth's crust slowly collided, and others have been worn away by weathering and erosion. ... Floods and landslides can change landforms in a matter of seconds. Volcanic eruptions can also change landforms quickly.

c, because the american revolution was from 1765 to 1783.