B. Took around half an hour to complete.
The complete predicate includes the verb and the rest of the sentence.
<span>In the choices indicated above, the sentence which contains correct comma usage is this one:
D. Swimming in the cool water, Colton felt extremely relaxed.
This sentence is composed of dependent and independent clauses. Comma is used instead of using conjunctions.</span>
C. There is no mention or anything revolving Romance. Anyone who read or seen it would know.
