Most destructive kind of mass movement a. Slump b. Mudflow c. Landslide d. Creep

The most destructive kind of mass movement is a Landslide.

A landslide is a mass movement of rock and soil that quickly slides down a steep slope, such as a mountain or cliff.

Landslides are estimated to cost billions of dollars in damage and kill between 25 to 50 people, annually, in the United States, alone.

I just took it on the test, it's Landslide.