gwd2-3,为什么是Ｃ

Not one of the potential investors is expected to make an offer to buy First Interstate Bank until a merger agreement is signed that includes a provision for penalties if the deal were not to be concluded.

c.is expected to make an offer to buy First Intersate Bank until  a merger agreement be signed by them with a provision for penalties if the deal were

答案Ｃ中　be signed by them是什么语法结构，如果是until a merger agreement is signed那我肯定会选Ｃ

谢谢!