单项选择题

某化学反应A2→2A的ΔrH9m(300K)=400.5KJ·mol-1,ΔrH9m(400K)=305.5KJ·mol-1,则有()

A.2Cp·m(A)>Cp·m(A2
B.2Cp·m(A)<Cp·m(A2
C.2Cp·m(A)=Cp·m(A2
D.Cp·m(A)>Cp·m(A2