which sentence is an example of a theme

A. James changes from being shy and timid to being confident and assertive.
B. The story takes place in modern-day australia in a beach town
C. Staying true to what you believe no matter the consequences is an example of bravery.
D. A student who has always struggled in school is inspired by his science teacher who encourages him to apply for a marine biology scholarship

C. Staying true to what you believe no matter the consequences is an example of bravery.