Diesel engines emiting 题

选项C为啥错？

Diesel engines burn as much as 30% less fuel than gasoline engines of 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 as emit far less carbon dioxide gas and far fewer of the other gasses having

C.    of comparable size, and also they emit far fewer carbon dioxide and other gasses that have

D.    that have a comparable size, and also they emit far fewer of the other gasses having

E.     that have a comparable size, as well as emitting far fewer of the other gasses having

选a。后面一个分句作状语，主语为前半个句子的主语。

c错在they指代不清，可以是前者也可以是后者

接受they指代不清的解释。

请问：A和B中far fewer of the other gasses ，为何使用of?

far less carbon dioxide gas 没有加of。如何解释？

谢谢！

请问：A和B中far fewer of the other gasses ，为何使用of?

far less carbon dioxide gas 没有加of。如何解释？

谢

up！！

far fewer of the other gasses

可以不加 OF 吗？