I think it is C because A is missing commas, B doesn't need them and D doesn't need one.
Answer:
Silas is not just Bod's protector but the protector/peacekeeper of all things supernatural.
Answer: "It's a dog" and "Who's that?"
Explanation:
The comma is putting together and shortening 'it is' and 'who is'.
Answer:
"It will make readers associate Stylin' Shades with being a good person"
Explanation:
Well I just looked at it and the key words "you'll know you've made the world brighter for someone else." and knew that it was for being a "good person"
