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

I am bit surprised that this question is from GMATPREP. Answer choices do not sound natural, but we can use POE to eliminate wrong answers.

Diesel engines burn as much as 30% less fuel than gasoline enginesof comparable size, as well as emitting far less carbon dioxide gas and far fewer of the other gasses that have been implicated in global warming.

A. of comparable size , as well as emitting far less carbon dioxide gas and far fewer of the other gasses that have
B. of comparable size, as well
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