That’s up to you, something you would like to tell yourself in the future, we don’t know how you are, what you like, etc.
I would say the theme is literary. The kid who doesn't study gets a bad grade while the one who did is the first one finished. But it isn't stated explicitly (as a direct or stated theme would be). I hope this helps.
B. a letter, sorry if im wrong! it said he had ate a piece of paper, so it must be b.
