On the Earth, When an Astronaut Throws a 0

Multiple Choice

On the earth, when an astronaut throws a 0.250-kg stone vertically upward, it returns to his hand a time T later. On planet X he finds that, under the same circumstances, the stone returns to his hand in 2T. In both cases, he throws the stone with the same initial velocity and it feels negligible air resistance. The acceleration due to gravity on planet X (in terms of g) is

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