I had to decide between C and E and I chose C. any ideas why E is preferred over C ?

annrae wrote:As the price of gasoline rises, which makes substituting alcohol distilled from cereal grain attractive, the prices of bread and livestock feed are sure to increase.
(A) which makes substituting alcohol distilled from cereal grain attractive
(B) which makes substituting the distillation of alcohol from cereal grain attractive
(C) which makes distilling alcohol from cereal grain an attractive substitute
(D) making an attractive substitution of alcohol distilled from cereal grain
(E) making alcohol distilled from cereal grain an attractive substitute

I think the OA is correct. The reason: alcohol (noun) is parallel with gasoline (noun).

Answer choice C is incorrect because distilling alcohol (verb) is not parallel with gasoline (noun).

The OA is correct because 'making' is the only way to start the phrase, since it must be parallel with 'rises'. That only leaves answer choices D and E. E is more concise then D, and therefore the answer.

**The key to this one, and many others, actually lies in looking at the answer choices given. 3 of the choices have 'which makes' and two have 'making'. Right there, it's an either or situation. Making the right grammatical choice there gives you a 50/50 chance at the right answer. You should never be choosing between answers A and E, for example, because the difference between those choices is so distinct.

its a cause n effect question, so verb+ing form is preffered.