# Three concentric spherical shells have radii a, b, and c(a < b < c) and have surface charge densities $\sigma$,$-\sigma$ and $\sigma$ respectively. If $V_A,V_B,V_C$ denote the potentials of the three shells, then, for c = a + b, we have :
( A ) $V_C{\neq}V_B{\neq}V_A$
( B ) $V_C=V_B{\neq}V_A$
( C ) $V_C=V_B=V_A$
( D ) $V_C=V_A{\neq}V_B$