The enthalpy of hydrogenation of benzene is $-51.0$ kcal/mol. If enthalpy of hydrogenation of 1,4 -cyclohexadiene and cyclohexene is $-58 \mathrm{kcal} / \mathrm{mol}$ and $-29 \mathrm{kcal} / \mathrm{mol}$, respectively, what is the resonance energy of benzene?
(a) $29 \mathrm{kcal} / \mathrm{mole}$
(b) $36 \mathrm{kcal} / \mathrm{mole}$
(c) $58 \mathrm{kcal} / \mathrm{mole}$
(d) $7 \mathrm{kcal} / \mathrm{mole}$