<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. To clearly state the main idea of the paragraph
Answer:
Apposition is a grammatical construction in which two elements, normally noun phrases, are placed side by side so that one element identifies the other in a different way; the two elements are said to be in apposition.
Explanation: