GMATPrep CR question

[RonPurewal]

in this problem, the task is to explain why something is NOT happening in the capital, even though it IS happening throughout the rest of the country.

thus, right from the start, it should be clear that the explanation—whatever it might be—MUST be something that differs between the capital and the other areas.
choice D contains no such distinction, so it is automatically irrelevant. any further thinking about D is a waste of your time.

in fact, by making this very basic observation ^^ we are immediately down to just A and E. none of the other three choices has anything to do with 'capital vs. other areas'.

[RonPurewal]

...and do note that this is a VERY basic observation: differences can only be explained by other differences.
this is a ground-level, common-sense realization. in fact, this idea is so basic that, in any analogous real-world situation, EVERYONE would IMMEDIATELY realize it.

e.g.,
I failed the test. Laura passed the test. Why?

• you can probably invent lots and lots of reasons why this might be true—but ALL of them will be differences between me and laura (or between my version of the test and hers, or between the circumstances under which we were tested, or whatever). ANY valid explanation, no matter how crazy, MUST be 'X for laura, whereas not-X for me'.

• it should be immediately obvious that anything without such a distinction (e.g., The test was hard) does not, and cannot, explain why one person passed but the other failed.