E it is. Very good explanation by Mitch earlier.

I received a PM asking me to clarify the difference between of and for.
There are no clearcut rules; prepositional modifiers serve many uses. That being said:

OF often serves to describe the NATURE of the noun being modified:
In a penalty OF one hundred dollars, the prepositional modifier describes the NATURE of the penalty.

FOR often serves to describe the CAUSE of the noun being modified:
In a penalty FOR speeding, the prepositional modifier describes the CAUSE of the penalty.

TO often serves to describe the PURPOSE of the noun being modified:
In a penalty TO deter crime, the prepositional modifier describes the PURPOSE of the penalty.

When prepositions change in the answers, the SC likely is testing an idiom.
The good news is that the current incarnation of the GMAT is placing much less emphasis on idioms.
Any answer choice that contains an idiom error is likely to contain at least one other error.
If you're not certain which preposition or idiom is needed in any particular instance, LOOK FOR A DIFFERENT ERROR.

GMATGuruNY wrote:I received a PM asking me to clarify the difference between of and for.
There are no clearcut rules; prepositional modifiers serve many uses. That being said:

OF often serves to describe the NATURE of the noun being modified:
In a penalty OF one hundred dollars, the prepositional modifier describes the NATURE of the penalty.

FOR often serves to describe the CAUSE of the noun being modified:
In a penalty FOR speeding, the prepositional modifier describes the CAUSE of the penalty.

TO often serves to describe the PURPOSE of the noun being modified:
In a penalty TO deter crime, the prepositional modifier describes the PURPOSE of the penalty.

When prepositions change in the answers, the SC likely is testing an idiom.
The good news is that the current incarnation of the GMAT is placing much less emphasis on idioms.
Any answer choice that contains an idiom error is likely to contain at least one other error.
If you're not certain which preposition or idiom is needed in any particular instance, LOOK FOR A DIFFERENT ERROR.

Thanks a lot Mitch. Makes the point a lot easier to understand.

(E) is the answer.

as least as and also parallelism

straight E.
parallel, correct comparison and no dedundant word.

E for sure!

IMO (C)
(E) CHANGES THE INTENDED MEANING

IMO E

After reading the comments, I'd Say E too

1st split: the comparison is between the fuel penalties incurred by "Wind resistance created by opening windows while driving" and by "using air conditioning"

Any choice that doesn't clarify this relationship is wrong => cross A, B & D

Between C & E, "as great as or greater than" sounds awkward and wordy.

Hence, choose E

Wind resistance created by opening windows while driving results in a fuel penalty as great or greater than is incurred by using air conditioning.

(A) as great or greater than is incurred by using air conditioning
(B) that is as great or greater than is incurred using air conditioning
(C) as great as or greater than that of using air conditioning
(D) at least as great as air conditioning's
(E) at least as great as that incurred by using air conditioning

Primarily, most of us would have shortlisted A or C or E

Here is the explanation why A and C are Wrong

You cannot eliminate A just because it is wordy, there is a very concrete sentence construction Flaw

A says Wind resistance created by opening windows while driving results in a fuel penalty as great or greater than is incurred by using air conditioning.

as great or greater than is incurred by using ....

What does is refer to, here?

Is is verb and must be parallel to another Verb in (x is y than) construction. And that another verb is results

So it means "is" refers to the subject of the verb "results" as well ---> Wind resistance

as great or greater than (wind resistance) is incurred by using air conditioning --> This we can clearly see as wrong meaning

Hence Eliminate

For C

(C) as great as or greater than that of using air conditioning

Replace that with the apt noun - That is fuel penalty.

So it becomes

(C) as great as or greater than fuel penalty of using air conditioning --> Isint parallel

Remebr x than Y has to be parallel contruction

Fuel penalty as great/greater THAN ( Requires parallel to whatever before than/as )
x than (y of) is not parallel

It should be
x than y

Hence Eliminate C

For E : Everything is in place

X than Y is parallel
Penalty => That (Refers back to penalty)

Cheers,
Akash

Wind resistance created by opening windows while driving results in a fuel penalty as great or greater than is incurred by using air conditioning.

(A) as great or greater than is incurred by using air conditioning
(B) that is as great or greater than is incurred using air conditioning
(C) as great as or greater than that of using air conditioning
(D) at least as great as air conditioning's
(E) at least as great as that incurred by using air conditioning

Primarily, most of us would have shortlisted A or C or E

Here is the explanation why A and C are Wrong

You cannot eliminate A just because it is wordy, there is a very concrete sentence construction Flaw

A says Wind resistance created by opening windows while driving results in a fuel penalty as great or greater than is incurred by using air conditioning.

as great or greater than is incurred by using ....

What does is refer to, here?

Is is verb and must be parallel to another Verb in (x is y than) construction. And that another verb is results

So it means "is" refers to the subject of the verb "results" as well ---> Wind resistance

as great or greater than (wind resistance) is incurred by using air conditioning --> This we can clearly see as wrong meaning

Hence Eliminate

For C

(C) as great as or greater than that of using air conditioning

Replace that with the apt noun - That is fuel penalty.

So it becomes

(C) as great as or greater than fuel penalty of using air conditioning --> Isint parallel

Remebr x than Y has to be parallel contruction

Fuel penalty as great/greater THAN ( Requires parallel to whatever before than/as )
x than (y of) is not parallel

It should be
x than y

Hence Eliminate C

For E : Everything is in place

X than Y is parallel
Penalty greater than That (Refers back to penalty)
Penalty as great as that (Refers back to penalty)

Cheers,
Akash

E.

E is better.

IMO....E