A total charge of Q is distributed over two concentric hollow spheres of radii r and R `(R gt r)` such that the surface charge densities on the two spheres are equal. The electric potential at the common centre is :

Options

A. `(1)/(4 pi epsilon_(0))(Q (R-r))/(R^(2) + r^(2))`
B. `(1)/(4 pi epsilon_(0)) (Q(R + r))/(2(R^(2) + r^(2)))`
C. `(1)/(4 pi epsilon_(0)) (Q(R + r))/(R^(2) + r^(2))`
D. `(1)/(4 pi epsilon_(0)) (Q(R-r))/(2(R^(2) + r^(2)))`