One of the biggest differences between 500/600 and 700+ test takers is the ability to get around feeling like, at first pass, you have no idea how to answer a test question. Smart test takers recognize that the best place to uncover clues on how to answer a challenging question is to scan the answer choices.

A trend you may have noticed from previous posts is – and we’ll say it again! – the GMAT is not really testing your ability to do math or understand complex grammar rules, but rather, how you critically think and reason. This is why Critical Reasoning questions exist, and why they can be tough questions for first-time test takers to tackle. But back to scanning answer choices. Let’s start with this sentence correction question:

A 2009 study from the California State Housing Authority concluded that conversion from ownership to rental properties has often been difficult; it has been more common for some townhouses and other “attached” homes that are relatively small and old, located in central cities.

(A) difficult; it has been more common for some townhouses and other “attached” homes that are relatively small and old, located in central cities.

(B) difficult; it has been more common for some townhouses and other “attached” homes that are relatively small, old, and that are located in central cities.

(C) difficult; it has been more common for some townhouses and other “attached” homes, which are relatively small and old, and located in central cities.

(D) difficult: it has been more common for some townhouses and other “attached” homes that are relatively small and old and located in central cities.

(E) difficult: it has been more common for some townhouses and other “attached” homes that are relatively small and old, and located in central cities.

When most of us read this question prompt, we have difficulty ascertaining exactly what is incorrect about the sentence. But, if we were to go right to the answer choices, we’d notice that the punctuation at the beginning of the sentence (semicolon vs. colon) is one thing that varies across answer choices.

Now, would we have figured out, even after reading the prompt several times, that punctuation was an issue? Very unlikely, particularly as it seems like something that is too “simplistic” for the GMAT to be assessing. However, when we scan through the answer choices it becomes obvious, saving us a great deal of time.

If we realize that a colon is what is needed because the second part of the sentence is an additional detail that clarifies the study from the 2009 study, then we are in fantastic shape because we are only left with two answer choices – (D) and (E).

Trying to figure out the second decision point is also tough – part of why this is a 700+ level sentence correction question – but again, scanning between the two remaining answer choices makes this question much more manageable. The only difference between the two answer choices is the comma after the word “old.” The correct answer choice is (D) because placing a comma before the conjunction “and” is incorrect – this would only be using in the case of a separate clause.

Okay, yes, the GMAT is testing your core understanding of punctuation here. You do need to understand proper usage of colons, semicolons, commas, and conjunctions for the exam. However, this answer choice shows how impossible it is to identify minute errors without letting the answer choices guide you down the right path.