GMATPrep - modifier Difficult one

[GMATMadeEasy]

12. 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.

A. what they had not previously considered possible -- better control, if not eradication, of the other infections such as
B. what they had not previously considered a possibility -- better control, if not
eradication, of such infections like
C. something they had not previously considered possible -- better control, if not
eradication, of such infections as
D. something not considered a previous possibility -- better control and perhaps
eradication, of other infections such as
E. the possibility of what they had not previously considered possible -- better
control and possibly eradication of infections like

WHat is the difference between A and C ?

[Frankenstein]

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.

A. what they had not previously considered possible -- better control, if not eradication, of the other infections such as
B. what they had not previously considered a possibility -- better control, if not
eradication, of such infections like
C. something they had not previously considered possible -- better control, if not
eradication, of such infections as
D. something not considered a previous possibility -- better control and perhaps
eradication, of other infections such as
E. the possibility of what they had not previously considered possible -- better
control and possibly eradication of infections like

I think the use of definite article 'the' is problematic. I have checked this on MGMAT forums as well. I will post Ron's post:

There are 2 problems with A.
- Major problem is "THE other infections." THE is too definitive here, carrying the connotation of "every single one of the other infections."
* THE is also incompatible with "such as":
- Correct: I never read this book, but I read the other books on the shelf.
- Correct: I never read this book, but I read other books on the shelf, such as "Right Hand, Left Hand" and "The Rise and Fall of the Third Reich."
- Incorrect: I never read this book, but I read the other books on the shelf, such as "Right Hand, Left Hand" and "The Rise and Fall of the Third Reich."
- Minor problem is "what they had not..." vs. "something they had not..." The "what" construction is awfully strong, suggesting that this was THE ONE THING they hadn't thought possible.
* As an analogy, compare the meanings of "I want to do what I love for a living" and "I want to do something I love for a living." The first suggests that the speaker has one particular field in mind; the second doesn't.

[amit2k9]

between A and C, A usage of the article is making the diseases definitive.
C makes the usage general,thus C is better.