prep的一道语法题的疑问

天蝎座1107

If current trends contine, 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 higer than were those这里those指代emissions level与emissions比较错误

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没必要用would if一般现在时 又有by the year 2010所以主句will 然后it错 因为it是全部指代前面那个将来的level 还有was的补出是多余 因为这里不补出不会引起歧义

D) would soar to a level more than one-third higher than those those指代emissions却和level比较错

E) would soar to a level more than one-third higher than they were they也是全部指代到2010年的carbon emissions错 这样又是level与emissions比较错

If一般现在时 by the year 2010也暗示要用will 所以在A和B中选 tha