Hello Everyone!
If you're running into this question for the first time on the 2020 Official Guide, welcome! Let's start by taking a quick glance over the original question, and highlight any major differences we can find in orange:
Hurricanes at first begin traveling from east to west, because that direction is the way the prevailing winds in the tropics blow, but they then veer off toward higher latitudes, in many cases changing direction toward the east before dissipating over the colder, more northerly waters or over land.
(A) Hurricanes at first begin traveling from east to west, because that direction is the way the prevailing winds in the tropics blow, but
(B) At first, hurricanes travel from east to west, because that is the direction of the prevailing winds in the tropics, but
(C) While hurricanes travel from east to west at first, the direction of the prevailing winds blowing in the tropics, and
(D) Because hurricanes at first travel from east to west, since it is the direction of the prevailing winds in the tropics,
(E) Hurricanes, beginning by traveling from east to west, because this is the direction of the prevailing winds in the tropics,
After a quick scan over the options, a few differences pop out:
1. How it talks about hurricanes traveling
2. How it talks about prevailing winds
3. How they end (no conjunction / and / but)
This seems like a lot, right? Whenever you see a GMAT question with this much variation between the options, it's time to start looking for bigger picture problems.
One of the big picture issues we can look at is making sure each sentence has a clear subject and verb. With this many modifiers, commas, and phrases stacked together, it's likely that at least 1-2 options will be missing a subject or verb. Let's look closely at each option and cross out any modifiers, prepositional phrases, or non-essential phrases to see if we're left with a complete sentence:
(A) Hurricanes at first begin traveling from east to west, because that direction is the way the prevailing winds in the tropics blow, but they then veer off toward higher latitudes, in many cases changing direction toward the east before dissipating over the colder, more northerly waters or over land. --> OK
(B) At first, hurricanes travel from east to west, because that is the direction of the prevailing winds in the tropics, but they then veer off toward higher latitudes, in many cases changing direction toward the east before dissipating over the colder, more northerly waters or over land. --> OK
(C) While hurricanes travel from east to west at first, the direction of the prevailing winds blowing in the tropics, and they then veer off toward higher latitudes, in many cases changing direction toward the east before dissipating over the colder, more northerly waters or over land. --> WRONG
(There is no clear subject or verb here - just a series of modifiers, prepositional phrases, and interjections piled up together!)
(D) Because hurricanes at first travel from east to west, since it is the direction of the prevailing winds in the tropics, they then veer off toward higher latitudes, in many cases changing direction toward the east before dissipating over the colder, more northerly waters or over land. --> WRONG
(While what you're left with is technically a complete sentence, it has lost so much of its intended meaning that it doesn't make sense on its own.)
(E) Hurricanes, beginning by traveling from east to west, because this is the direction of the prevailing winds in the tropics, they then veer off toward higher latitudes, in many cases changing direction toward the east before dissipating over the colder, more northerly waters or over land. --> WRONG
(This sentence has a subject, but no verb!)
We can eliminate options C, D, & E because they are missing a subject, verb, or both.
Now that we have it narrowed down to only 2 options, let's look more closely to find other problems and narrow it down to one option:
(A) Hurricanes at first begin traveling from east to west, because that direction is the way the prevailing winds in the tropics blow, but
This option is INCORRECT for a couple reasons. First, the phrase "at first begin" is redundant - "at first" and "begin" mean the same thing, so you don't need to say them both. The other phrase we highlighted is also a bit clunky and overly wordy as well.
(B) At first, hurricanes travel from east to west, because that is the direction of the prevailing winds in the tropics, but
This is the CORRECT choice! It's not redundant, there is a clear subject and verb, and it's not overly wordy!
There you have it - option B is the correct choice!
Don't study for the GMAT. Train for it.
