求教新prep中一题

217.
                (30418-!-item-!-188;#058&005391)     (T-3-Q17. ��ɽ-7-14)

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.

A. 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

B. 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

C. 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

D. 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

E. 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

答案是A

想问的是为什么A选项最后是were, 它不是deal的谓语么？