A spherical capacitor consists of two concentric, thin conducting spherical shells of radii \(a\) and \(b\) (where \(a < b\)). The inner shell carries a net charge \(+Q\) and the outer shell carries a net charge \(-Q\). Which of the following best describes the graph of the electric energy density \(u_E\) stored in the electric field as a function of radial distance \(r\) from the common center?