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

这里答案是A，可GWD31-02-03给的答案可是C呀！到底哪个对呢？

我比较倾向C，只是不清楚这个动词原型有什么说法

望指教！

A不对啊,THAT不能指代动词前面的名词的啊,前面有套答案是C,有NN说是

虚拟语气的用法,想问为什么要用BE....ji