https://www.sparknotes.com/lit/flies/section12/
It would be a, because thats the only one that is true
<span>The sentence which does not contain any errors in comma usage is:
A. He can juggle several tennis balls, but he doesn't like tennis.
In this sentence, comma is used to denote a brief pause at the same time separates the dependent and independent clauses for emphasis.</span>
