Prep Test2-58 if 之后的虚拟语气

If current trends continue, by the end of year 2010 carbon emissions in the United States will soar to a level more than one-third higher than were those in 1990, according to official projections.

(A) will soar to a level more than one-third higher than were those

(B) will soar to a level more than one-third higher than that

(C) would soar to a level more than one-third higher than it was

(D) would soar to a level more than one-third higher than those

(E) would soar to a level more than one-third higher than they were

答案是B,给出E不对的理由是主语应该使用will, 而不是would. 我想请问If 作为条件的虚拟语气，后面不应该是用过去将来式的吗？还有，说E中的they无指代。不可以就近指代carbon emissions吗？

明白啦，多谢指教。