A Satellite Having Orbital Speed V Orbits a Planet of Mass

Multiple Choice

A satellite having orbital speed V orbits a planet of mass M. If the planet had half as much mass, the orbital speed of the satellite at the same distance from the center would be

A) V $\sqrt { 2 }$ .
B) 2V.
C) V.
D) V/ $\sqrt { 2 }$ .
E) V/2.