[单选题]
A satellite encircles Mars at a dijz) d;;tj dsira78c/vstance (xjgg7qq,a v0 above its surface equal to 3 times the radius of Mars. The acceleration of gravity of the satellite, as compared to the acceleration of gravity on the surface ofgg( xvqq7,j0a Mars, is
A. zero.
B. the same.
C. one-third as much.
D. one-sixteenth as much.