Ⅱ型呼吸衰竭的血气分析特点是()

A.PaO<50mmHg，PaCO>60mmHg

B.PaO>60mmHg，PaCO<50mmHg

C.PaO<60mmHg，PaCO>50mmHg

D.PaO<55mmHg，PaCO>50mmHg

E.PaO<60mmHg，PaCO<50mmHg