He told you that because you have known the truth.
A. needs not have
B. need not have
C. need not has
D. does not need have
网友回答
A. needs not have
(答案→)B. need not have
C. need not has
D. does not need have
解析：考查情态动词表示虚拟语气的用法：needn’t have done“本不必做而做了”，句意是：因为你已经知道事实了，他本没有必要告诉你的。选B