If on the concentric hollow spheres of radii $r$ and $R( > r)$ the charge $Q$ is distributed such that their surface densities are same then the potential at their common centre is

  • A

    $\frac{{Q\left( {{R^2} + {r^2}} \right)}}{{4\pi \varepsilon _0\left( {R + r} \right)}}$

  • B

    $\frac{{QR}}{{R + r}}$

  • C

    Zero

  • D

    $\frac{{Q(R+r)}}{{4\pi \varepsilon _0\left( {{R^2} + {r^2}} \right)}}$

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