Why Does the Top of a Rotational Slide Tilt Back

Multiple Choice

Why does the top of a rotational slide tilt back into the slope?

A) As the slide moves away from its head scarp, material slides back into the gap.
B) The slide mass rotates on a circular curving surface, so everything on it rotates backward.
C) The inertial pull of the fast-moving slide leaves a gap behind at the top.
D) Since the slide mass pulls away from the head scarp, it leaves a gap that tilts backward.
E) Since the top of the mass is pulled forward, the bottom tilts back, just as you would if you slipped on ice.