Phobos, the Innermost Moon of Mars, Has an Orbital Period

Multiple Choice

Phobos, the innermost moon of Mars, has an orbital period that is less than 1 Martian day. This means that, as seen from Mars, Phobos appears to:

A) hover over one position all the time in a synchronous orbit.
B) rise in the west, moving eastward.
C) oscillate back and forth in the sky, never rising or setting from a given location.
D) rise in the east, traveling westward.