As here is no electric and magnetic field so ignore m to calculate the energy of orbital. As here atom is multi-electron so (n+l) rule is applicable here. This rule says those orbitals which have more value of (n+1) will have more energy. ln(A),n+1=1+0=1 ln(B),n+1=2+0=2 ln(C),n+1=2+1=3 ln(D),n+1=3+2=5 ln(E),n+1=3+2=5 So (D) and (E) will be of equal energy.