“a+b=-2”是“直线x+y=0与圆(x﹣a)2+(y﹣b)2=2相切”的(     )

“a+b=-2”直线x+y=0与圆(xa2+yb2=2相切    

A.既不充分也不必要条件             B.必要不充分条件  

C.充要条件                         D.充分不必要条件

答案

D

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