If current trends continue, by the year 2010 carbone 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