A Satellite Encircles Mars at a Distance Above Its Surface

Multiple Choice

A satellite encircles Mars at a distance above its surface equal to 3 times the radius of Mars. The acceleration of gravity at the satellite, as compared to the acceleration of gravity on the surface of Mars, is

A) one-ninth as much.
B) zero.
C) the same.
D) one-third as much.
E) one-sixteenth as much.