Concept:For a reaction, spontaneity is determined by the Gibbs free energy change: ΔG=ΔH−TΔS.Explanation:An endothermic reaction has ΔH>0.A loss in entropy means ΔS<0.So −TΔS is positive, making ΔG=ΔH−TΔS positive at all temperatures.Since ΔG>0, the reaction is not spontaneous.Answer:C. not be spontaneous