Three identical bodies, each of mass m, are located at the vertices of an equilateral triangle with side r…..

Q: Three identical bodies, each of mass m, are located at the vertices of an equilateral triangle with side r. The speed with which they move if they all revolve under the influence of one another’s gravitation in a circular orbit circumscribing the triangle while still preserving the equilateral triangle ?

(a) $ \displaystyle \sqrt{\frac{G m}{3 r}} $

(b) $ \displaystyle \sqrt{\frac{G m}{ r}} $

(c) $ \displaystyle \sqrt{\frac{2 G m}{ r}} $

(d) $ \displaystyle \sqrt{\frac{G m}{2 r}} $