Electric potential on the surface of a solid sphere of radius R is V . Then potential at $\;r=\large\frac{R}{2}\;$ is

Question

$(a)\;\large\frac{V}{4}\qquad(b)\;\large\frac{V}{2}\qquad(c)\;\large\frac{3 V}{4}\qquad(d)\;None\;of\;these$