A protein undergoes reversible thermal denaturation from its initial state N to denatured state D according to \(N \rightleftharpoons D\). At \(60^\circ C\), the concentrations of both N and D are equal at equilibrium, and the standard enthalpy change of denaturation is \(666\ kJ\ mol^{-1}\). The standard entropy change \((\Delta S^\circ)\) in \(kJ\ K^{-1}\ mol^{-1}\) of the protein upon denaturation at \(60^\circ C\) is closest to