Brittani said, “I can’t read this signature. I think it belongs to Terrance.”

This sentence illustrates the following comma rule:

A. Commas are used to set off a speaker’s exact words from the rest of the sentence
B. A comma is used before a coordinating conjunction in a compound sentence
C. A comma is used after a dependent clause when the clause begins a sentence
D. A comma is used to separate items in a series