Hey
woohoo921Happy to help.
Yes, it is true that "
when two ICs are connected with FANBOYS, the conjunction must be preceded by a comma". But, this
does NOT mean that
every time we see a "Comma + FANBOYS", it has to be followed by an IC. FANBOYS also connect a list of phrases and even a list of words. And, thanks to the Oxford Comma Rule, you will find "comma + FANBOYS" right before the last entity in every list of three or more words, phrases, or clauses. For example:
a. I play cricket, football, and basketball.
So, should we expect an IC after ", and"? No, right?
Yes, the use of the comma in choice C can be called purely stylistic. Choice C contains the correlative connector "not (x) but (y)". Now, we could choose to separate the not-phrase from the but-phrase with a comma if each phrase is long enough or if we wish demarcate the end of the not-phrase.
There are much worse errors in the other choices to be worrying about the comma in choice C. So, the second take-away from this question is to learn to prioritize errors in GMAT SC. There are some errors that are more deterministic than others. Try to create a mental note of that hierarchy.
I hope this helps improve your understanding.
Happy Learning!
Abhishek