A uniform sphere of mass M and radius R exerts a force F on a small mass m situated at a distance of 2R from the centre O of the sphere. A spherical portion of diameter R is cut from the sphere as shown in the figure above. The force of attraction between the remaining part of the sphere and the mass m will be...

a) 7F/9
b) 2F/3
c) 4F/9
d) F/3

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