Sentence Correction

The success of the program to eradicate smallpox has stimulated experts to pursue what they had not previously considered possible - better control, if not eradication, of the other infections such as measles and yaws.

1. what they had not previously considered possible - better control, if not eradication, of the other infections such as
2. what they had not previously considered possible - better control, if not eradication, of the other infections like
3. something they had not previously considered possible - better control, if not eradication, of such infections as
4. something had not considered a previous possibility- better control, and perhaps eradication, of other infections such as
5. the possibility of what they had not previously considered - better control and possibly eradication of infections like

Source: GMAT Prep.

[spoiler]OA: C. [/spoiler]

This one is tough because again...the difference between the last two is meaning. Does anyone have any better trick to tackle these, other than reading every word for comparison.

You can eliminate 1(A) because of the words "the other infections". This is ambiguous you should instantly ask yourself, what other infections are they referencing.

You can eliminate 2 (B) and 5(E) because "like" cannot introduce examples.

You can eliminate 4(D) because "had not" does not have a subject.

This problem was tough, but this one was more a pure grammar problem rather than meaning.

My POE for this question was pretty straight forward: I used such as/like for the 3/2 split, and then eliminated D for "had not considered a previous possibility".

Then the choice comes down to A or C. Difference between the two are "what..." and "something", and "such infections" and "the other infections". In speaking language, I'll probably avoid "such infections as", but I know that the usage is correct for GMAT. (oh hey, maybe a little trick here is that GMAT will make what "sounds" wrong but what is grammatically right the right answer when it is down to 50/50).

osirus0830, yes, I should have used definite article to eliminate A, but unfortunately definite article wasn't on my radar when I worked on this question.

You can eliminate A on the following reason.

the other infections such as is nothing but such infection as.

Usually what I do is if I left with 2 options, one is with such as and other is with such X as, I choose later one. 100% of time I got this correct.