A solid conducting sphere of radius \(a\) carrying a net charge \(+Q\) is concentric with an uncharged, thin spherical conducting shell of radius \(b\), where \(b > a\). A thin conducting wire containing an open switch connects the inner sphere to the outer shell. The switch is now closed, and the system is allowed to reach electrostatic equilibrium. Assuming the electric potential is zero at infinity (\(V(\infty) = 0\)), which of the following best describes the shape of the electric potential \(V(r)\) as a function of radial distance \(r\) from the center?