—Must I return the book this morning?

—No, you             . But you               return it before supper. [ ]

A. needn't; must

B. mustn't; can

C. mustn't; may

D. can't; need

在逻辑问题中，如果某一事件的发生取决于条件的否定，则这种因果关系称为（）逻辑。