Phobos Orbits Mars in a Prograde Orbit with a Period

Phobos orbits Mars in a prograde orbit with a period less than the rotational period of Mars itself.What consequence follows from this?

A) Phobos rises in the west and sets in the east.
B) Phobos rises in the east and sets in the west.
C) Phobos is in a stationary orbit, always over the same point on Mars.
D) The situation described violates Kepler's third law: The farther out an orbit, the longer its period.