Prep语法求教阿

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

A )is expected to make an offer to buy First Interstate Bank until a meger 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 sigh a merger agreement including a provision for penalties if the deal was

就是问一下：为啥if后面跟were, answer 居然是A...

多谢拉

不知其它选项是怎样的？会不会有错得很离谱的地方。

因为如果只看A和B的话，我会选A，B错误太多了。

排除之后留下A，我会理解成是虚拟語气，与现在相反的虚拟語气，be动词一律用were