That's definitely informal because of the contractions used such as "'cause" and "y"all" and also because of the word phrasing such as "chow down" and "totally awesome."
If the title is "After Hours in Kindergarten" then the theme is about what goes on in a kindergarten's experience while in school. It provides the theme and tells you what you’ll be reading about.
The answer is D, mood refers to how the audience feels.
