如图，四边形ABCD的对角线交于点O，下列哪组条件不能判断四边形ABCD是平行四边形                        （   ）              (      )

A．OA＝OC，OB＝OD	B．∠BAD＝∠BCD，AB∥CD
C．AD∥BC，AD＝BC	D．AB＝CD，AO＝CO