Three uniform spheres of mass M and radius R each are kept in such a way that each touches the other two. The magnitude of the gravitational force on any of the sphere due to the other two sphere is

Question

$$(a)\;\frac {\sqrt 3}{4}\frac{GM^2}{R^2} \quad (b)\;\frac{3}{2}\frac{GM^2}{R^2} \quad (c)\;\sqrt 3 \frac{GM^2}{R^2} \quad (d)\;\frac{\sqrt 3}{2} \frac{GM^2}{R^2}$$