Sentence Correction

Hey Mparakala,

Two reasons to prefer (E) over (A).

Reason #1:

(A) "The reason...is because..."

(B) "The reason...is that..."

Answer choice (A) is redundant. "Because" literally means "for the reason that". You wouldn't say "The reason I'm here is because I want to see you." You would say "I'm here because I want to see you."

Reason #2:

(A) "contain the chemical tryptophan that promotes"

(B) "contain the chemical tryptophan, which promotes"

Answer choice (A) uses an essential modifier ("that"). This means that the modifier is essential to the meaning of the sentence. But it isn't. If there were two types of tryptophan, one of which promoted an increase in serotonin and one of which did not, you would need to specify which one you meant, so the modifier would be necessary, and we would need "that".

In (E), we use the non-essential modifier ("which"). This just provides a little parenthetical explanation of what a tryptophan is. It isn't necessary to the meaning of the sentence, it just clarifies.

To make the difference clearer, we could look at other sentences:

The woman that I love is in Istanbul.

The woman, whom I love, is in Istanbul.

Can you feel the subtle difference here? In the first example, we are specifying the woman. It is not just any woman, it is the woman that I love. In the second example, we're just talking about the woman, and the fact that I love her is simply a little descriptive aside.

Hope that helps!

-t

Ditto everything that Tommy said. I just wanted to add - the GMAT is very unlikely to give you two answer choices that just depend on the difference between "that" v. "which." There will almost always be some other way we can narrow the answer choices down. In this case, it was the redundancy in "the reason... is because." Because the meaning distinction between "that" and "which" can be pretty subtle, there are usually other grammar issues in the wrong answer choice (see OG13 #12).

So - make sure you understand the distinction, but don't spend too much time deliberating on a that/which split. There will almost definitely be other issues to look for!