单项选择题

二元溶液,T,P一定时,Gibbs—Duhem方程的正确形式是()

A.X1dlnγ1/dX1+X2dlnγ2/dX2=0
B.X1dlnγ1/dX2+X2dlnγ2/dX1=0 
C.X1dlnγ1/dX1+X2dlnγ2/dX1=0 
D.X1dlnγ1/dX1–X2dlnγ2/dX1=0