The tone would be determined by the kind of people the author is writing for. A story for children is going to have a different tone than a graduate thesis even if they are on the same topic.
Hope that helps.
The answer would be c - interjection.
Interjections are words or phrases that express emotion.
Examples would be wow, awesome, ummm, etc.
These are not appropriate for formal writing but used constantly in daily communication.
I think it is A) persuade because the author is trying to convince the reader that soccer is the most popular sport in the world.
The answer is A. (Turns Out the lights)