—I saw Helen in the library this morning.

—No, it ______ her. She moved to France last week.   [ ]

A. can't be          

B. can be          

C. mustn't be

成都农商行仓单授信业务规定，经办行对借款人的授信期限原则在一年内（含），授信实际使用以不超过六个月（含）为限但可循环使用。