Does the sentence below require a comma before the coordinating conjunction?
The ballerina was slender and strong.
Yes, there should be a comma before "and" because there's always a comma before a conjunction.
No, there should not be a comma because only one of the clauses is independent (can stand by itself).
Yes, there should be a comma, because you might as well use as many commas as possible.
No, there should not be a comma because FANBOYS.
Andy plays the violin well, _____ the trumpet is his favorite instrument.