Use a comma to set off the words yes and no (for example: Yes, thank you), to set off a tag question from the rest of the sentence (for example: It’s true, isn’t it?), and to indicate direct address (for example: Is that you, Steve?).
Writing and Composition
Apply understanding of the conventions of standard English grammar, usage, and mechanics to make meaning clear and to strengthen style.
Demonstrate command of the conventions of standard English capitalization, punctuation, and spelling when writing.