Prep2-58 carbon emissions 用those还是that指代

58.        (27510-!-item-!-188;#058&003569)

If current trends continue, by the 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

答案为B，可是 carbon emissions 是复数，应该用those指代，A才是正确答案。请DN指正！

另外一种可能性是“that" 指代 “level"

同问. 不过A那个were是多余的. 我开始选的是D 

请仔细体会一下原句意思，比较的是level。

我做题时选了C。

请问：C除了would的错误外，后面的than it was有没有错？

it can be read soar to a level higher than that ...

这道题怎么NN都不来了看看呐 

请NN现身吧