Two ions 1 and 2, at fixed separation, with spin angular momentum operators S, and S, have the interaction Hamiltonian H = -JS S, where Jo. The values of S2 and S2 are fixed at S(S + 1) and S(S + 1), respectively. Which of the following is the energy of the ground state of the system? A. O B.-JSS C. -J[S(S+1)-S(S + 1)] D. (J/2) [(S+S) (S + S + 1) - S(S+1) - S(S+1)] E. -(J/2) [(S(S + 1) + S(S + 1))/(S + S) (S + S + 1)]