Deimos Remains Over Almost the Same Spot on Mars' Surface

Multiple Choice

Deimos remains over almost the same spot on Mars' surface. To remain over the same spot it must:

A) always have the same side facing Mars.
B) be in an orbit that is above the Martian equator.
C) be in an orbit that passes over the poles.
D) be at a distance over the Martian surface that is equal to the distance from the center of Mars to the surface.