None you should invest a quarter and put the rest away.
To remind the audience of the theme
There are three correct answers here:
1. The time of day during which the story takes place
2. The city in which the story takes place
3. The atmosphere or mood of the place.
Characters exist in the setting but aren't part of it in the same way we live on Earth but aren't part of the Earth's composition.
Writers make the characters voice sound like their own to make it feel like they are part of the story. They are the ones living the story as well. In conclusion, the authors make it sounds like the voice is their own to more excitement and help the reader imagine whats going on in the story.
Hope this helps!!