大全164 164.Because natural gas is composed mostly of methane, a simple hydrocarbon, vehicles powered by natural gas emit less of certain pollutants than the burning of gasoline or diesel fuel.
(A) less of certain pollutants than the burning of gasoline or diesel fuel
(B) fewer of certain pollutants than burning gasoline or diesel fuel do
(C) less of certain pollutants than gasoline or diesel fuel
(D) fewer of certain pollutants than does burning gasoline or diesel fuel
(E) less of certain pollutants than those burning gasoline or diesel fuel
key：（E）没问题

但总觉得E是廖化一类，“than those”不补上“do”不爽啊！是不是我想得太多了？

update:只能认为，没有歧义能省就省。但如果有其它一样但补全的选项，我想我会抛弃E的。