The Reaction PCl₃ (G) + Cl₂ (G)→PCl₅ (G) Is Exothermic

The reaction PCl₃ (g) + Cl₂ (g) →PCl₅ (g) is exothermic. The reaction is:

A) spontaneous at all temperatures.
B) nonspontaneous at all temperatures.
C) spontaneous at low temperatures.
D) spontaneous at high temperatures.
E) spontaneous if D G _rxn is positive.