A planet has two moons with mass for moon #1 as M and for moon #2 as 2M. Moon 1 rotates in a circular orbit of radius r. Moon 2 rotates in an orbit of radius 3r. How much stronger is the magnitude of gravitational force exerted by the planet on Moon 2 than that on Moon 1?
A) (9/2) times
B) 8 times
C) (2/9) times
D) (1/8) times