Satellites: a Satellite in a Circular Orbit of Radius R

Multiple Choice

Satellites: A satellite in a circular orbit of radius R around planet X has an orbital period T. If Planet X had one-fourth as much mass, the orbital period of this satellite in an orbit of the same radius would be

A) 4T.
B) 2T.
C) T .
D) T/2.
E) T/4.