Diesel engines burn as much as 30 percent less fuel as gasoline engine

“They” in the answer is ambiguous

Posted from my mobile device

They can refer to the subject of previous clause in parallelism. So they is acceptable in C.

I think the construct should be "as much as ... as"
So, I chose (B)
Another reason to eliminate C is "have been"

Original Option A:
Diesel engines burn as much as 30 percent less fuel as gasoline engines with comparable size do, and they emit far less carbon dioxide and other greenhouse gases, which have been determined to be contributing to global warming.

Intended Meaning:
1. Diesel Engine burn =<30% less fuel, than gasoline engine with same size.
2. Diesel Engine emit far less CO2 and other green house gases, which (gases) contribute to global warming.

Sentence exam on:
1. Comparison: not similarity (as much as X, as Y) but degree of superiority, (as much as X, than Y)
2. Tense: contributing (present participle) vs to contribute (Infinitive verb)
The infinitive refers to a complete action while the present participle refers to an ongoing action
3. conjuction: usage of "and"

(A) as gasoline engines with comparable size do,
and
they emit far less carbon dioxide and other greenhouse gases, which have been determined to be contributing
Flaw:
1. Wrong comparison, it says DE = GE (limiting only with comparable size)
2. Tense error "contributing"
3. X as much as A, than Y - correct idiom.

(B) as gasoline engines of comparable size do,
emitting far less carbon dioxide and other greenhouse gases
, which they have determined to contribute
Flaw:
1. Intended meaning error, "emitting far less carbon dioxide and other greenhouse gases" works as a information between two comma.
comparable size modifys "Emitting", where as it must modify DE.
2. Wrong Idiom used for comparison between DE and GE, it shows DE is compared with comparable size, than GE.
3. they is ambigious, no clear referance, either is it gases or is it engines.

(C) than do gasoline engines of comparable size,
and
they emit far less carbon dioxide and other greenhouse gases
, which have been determined to contribute
Correct

(D) than do gasoline engines of comparable size,
and emitting far less carbon dioxide and other greenhouse gases
, which have been determined as contributors
Flaw:
1. Tense Error - Emit (present tense), emiting (present particle)
2. Comparison Flaw - as contributors, Intended meaning error
3. usage of "as" shows comparison, but usage of "to" is used for - expressing motion in the direction

(E) than gasoline engines whose size is comparable,
and they emit far less carbon dioxide and other greenhouse gases
, which have been determined as contributing
Flaw:
1. "whose" limits the comparison with only those GE, whose size id comparable, creates intened meaning flaw
2. usage of "as" shows comparison, but usage of "to" is used for - expressing motion in the direction
3. tense error - "Contributing"

egmat since there is no use of comparable words such as more , less or any other how can we use than?

KarishmaB GMATNinja
x as much as Y - so cant the answer be B
Can you throw some light on this ?

less fuel as X
less fuel than ✓