Three concentric spherical shells have radii a, b and c (a<b<c) and have surface charge densities $\mathrm{\sigma },-\mathrm{\sigma }$ and $\mathrm{\sigma }$ respectively. If V_A, V_B and V_C denote the potential of the three shells, then for c = a + b we have 

• A

  ${\mathrm{V}}_{\mathrm{C}}={\mathrm{V}}_{\mathrm{A}}\ne {\mathrm{V}}_{\mathrm{B}}$

• B

  ${\mathrm{V}}_{\mathrm{C}}={\mathrm{V}}_{\mathrm{B}}\ne {\mathrm{V}}_{\mathrm{A}}$

• C

  ${\mathrm{V}}_{\mathrm{C}}\ne {\mathrm{V}}_{\mathrm{B}}\ne {\mathrm{V}}_{\mathrm{A}}$

• D

  ${\mathrm{V}}_{\mathrm{C}}={\mathrm{V}}_{\mathrm{B}}={\mathrm{V}}_{\mathrm{A}}$