C, the antagonist. Unless you're talking about the anime Kill Me Baby. Then it's D, a minor character. But otherwise, don't mind that last sentence, The answer is C.
D. Mom should be capitalized because I believe it is a proper noun.
You can replace the word mom with a person's name. That is not always the case however. For example, I called my mom on my.... If you capitalized mom in this sentence and put a name then it wouldn't make sense because the word my was added. Hopefully this helps and makes sense. Good luck!!!
A seems the most right because if the girl is developing so is the setting because the girl is the setting
