请教NN一道GWD SC

请教NN一道GWD SC

这道题的正确答案是C, 但是我怎么也理解不了C当中be signed 的用法，还有be signed by them这个them的指代也有点不清晰吧，有没有大牛帮忙解释一下呀？谢谢

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.

1. 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
2. is expected to make an offer for buying First Interstate Bank until they sign a merger agreement including a provision for penalties if the deal was
3. is expected to make an offer to buy First Interstate Bank until a merger agreement be signed by them with a provision for penalties if the deal were
4. are expected to make an offer for buying First Interstate Bank until it signs a merger agreement with a provision for penalties included if the deal was
5. are expected to be making an offer to buy First Interstate Bank until they sign a merger agreement including a provision for penalties if the deal were

我觉得：IF ＋were 虚拟语气， if the deal were  not to be concluded ， a merger agreement (省略should ）be signed by them with a provision for penalties 。

不知道我的理解对否。

我觉得这题选A，C中的them没有指代的对象