Two Balls, a and B, of Mass M and 2m

Multiple Choice

Two balls, A and B, of mass m and 2m respectively, are carried to height h at constant velocity, but B rises twice as fast as A. The work the gravitational force does on B is

A) one quarter the work done on A.
B) one half the work done on A.
C) the same as the work done on A.
D) twice the work done on A.
E) four times the work done on A.