A small point of mass m is placed at a distance 2R from the centre 'O' of a big uniform solid sphere of mass M and radius R . The gravitational force on ' m ' due to M is $$F_1$$. A spherical part of radius R/3 is removed from the big sphere as shown in the figure and the gravitational force on m due to remaining part of M is found to be $$F_2$$ . The value of ratio $$F_1 : F_2$$ is

A

12 : 11

B

11 : 10

C

12 : 9

D

16 : 9