Hi astori17,

You're asking about a couple of ideas, so I'll do my best to address both points:

1) The GMAT tends to evenly distribute the "correct" answer among the 5 choices, so each answer is equally likely over the course of the entire Test. In terms of Sentence Corrections, if you saw 15 SCs, then it's likely that about 3 of the questions would have answer A as the correct answer. This will vary, of course, depending on how you're performing and the "randomizer" computer program, but it's a point worth noting. Since Answer A is a "duplicate" of the original sentence, there will be a few SCs that are grammatically correct, as is, and don't need to be changed.

2) The other point that you've brought up is sometimes referred to as the "intent" of the sentence (the idea that it's attempting to communicate). While understanding this idea can sometimes help you to choose the correct answer, it's usually NOT the first aspect of an SC that you should look at. The answer choices are usually grouped around certain grammar issues (verbs, pronouns, parallelism, etc.); by knowing these rules, you can quickly eliminate answer choices and "zero in" on the correct one.

As an aside, some Test Takers prefer to read the original sentence first and try to spot a grammar issue/problem. I've never been a fan of that approach though, since it doesn't immediately utilize the patterns/clues in the answer choices. I prefer to have any hints/patterns that are available in mind when I read the original sentence for the first time.

GMAT assassins aren't born, they're made,
Rich