In the diagram shown , the charge +Q is fixed another charge +2q and mass M is projected from a distance R from the fixed charge . Minimum separation between the charges if the velocity becomes $\;\large\frac{1}{\sqrt{3}}\;$ times of the projected velocity , at this moment

Question

$(a)\;\large\frac{\sqrt{3}R}{2}\qquad(b)\;\large\frac{1}{\sqrt{3}R}\qquad(c)\;\large\frac{1}{2R}\qquad(d)\;None\;of\;these$