GMAT Sentence Correction (SC) | Re: Diesel engines burn as much as 30% less fuel than gasoline

The sentence is actually taken form NYT
http://www.nytimes.com/2001/05/27/busin ... iesel.html

I guess option B, D, and E are wrong because of "having been" which acts as a verb (with an incorrect tense)

I found A a little awkward because of the phrase/modifier ", as well as emitting"