The greatest road system built in the Americas prior to the arrival of

This question was posted on a thread for a slightly different version of this question, from the Verbal Review. This thread is for the GMATPrep version -- if anyone sees this on an official GMATPrep test, please let us know if we've made any typos in the answer choices!


The version of (B) here is technically parallel: the greatest road system (1) was the Incan Highway and (2) extended from northern Ecuador through Peru to southern Chile. We have a subject (the road system) and two parallel verbs for that subject, so we can't eliminate (B) right away.

So now we find ourselves in a familiar position: we don't have four options with obvious grammatical errors, so we simply have to compare what's left to see which option is best.

The first glaring difference between (B) and (E) is the subject: "the greatest road system..." vs "the Incan highway". To see why that matters, here are some examples:

• "The greatest basketball player of all time was Michael Jordan."

This seems fine. "The greatest basketball player of all time" is the subject, and the noun after the linking verb ("was") gives us more information about that subject, telling us who exactly that player was.

But take a look at this version:

• "The greatest basketball player of all time was Michael Jordan and plays golf every day."

This is a bit funkier. Clearly, the point of the sentence was link an initially unidentified subject ("the greatest basketball player of all time") to a specific person (Michael Jordan). But then we're adding that the unidentified subject also plays golf every day? It doesn't really make sense to describe the golf habits of an unidentified subject ("the greatest basketball player of all time").

Even though the parallelism is technically okay in the second example above, using the specific person as the subject would be much clearer and better: "Michael Jordan was the greatest basketball player of all time and plays golf every day."

Now back to choice (B). The second verb ("extended") gives us specific information about an unidentified subject. In some contexts that might work, but in this case the sentence is trying to communicate specific information about a specific road. That's why the parallelism in (B), while technically okay, isn't ideal.

(E) avoids that issue altogether: "the Incan highway" is the subject, and that specific road is described as being the greatest road system and "extending from..." Does that make (B) wrong in a bubble? Maybe not. But the structure of (E) makes a bit more sense.

Also, the meaning of the "over 2,500 miles long" part is a bit clearer in (E):

• In (B), the "over..." part is dropped in as a comma-separated modifier, and the reader has to figure out what to do with it.
• In (E), that same modifier is tied directly back to the subject with a linking verb, so the meaning is clear and unambiguous.

Again, that doesn't make (B) WRONG, exactly, but it gives us another vote in favor of (E).

So (B) isn't terrible, but (E) is a better choice.

I hope that helps!