Four particles, each of mass \[M\]and equidistant from each other, move along a circle of radius \[R\] under the action of their mutual gravitational attraction. The speed of each particle is

• A. \[\sqrt{\frac{GM}{R}(1+2\sqrt{2})}\]
• B. \[\frac{1}{2}\sqrt{\frac{GM}{R}(1+2\sqrt{2})}\]
• C. \[\sqrt{\frac{GM}{R}}\]            
• D. \[\sqrt{2\sqrt{2}\frac{GM}{R}}\]