The answer should be B) because social media is a long distance communication tool for people, so not C) since that's false, that's where most danger is at is online, not D) because that wasn't the original purpose, but sadly its become popular now and not A) because that's incorrect.
Capitalize "Y" in you since it is the start of a statement
What sets off appositives in the sentence is the use of the quotation mark, comma (,). This indicates that the phrase is just an added information in the sentence, and if omitted will never change the whole thought or idea of the sentence. Aside from commas, parentheses or dashes can be used as well.
Plastic, oils from boats, air pollutants.
C. Bobby enjoyed sunsets, and they were often photographed by him.
