C would be the best because there is a story being told within another story and that is what a frame narrative is.
Do you mean grad speech? If so:
Here are some ways to write a grad speech:
1. Thank the Previous Speaker
2. Introduce Yourself
3. Share a Motivational Quote
4. Share Some Good Advice
5. Recall the Good Times
6. Restate Your Motivational Quote
7. Create a Call to Action
8. Thank Everyone
C. They reveal how the characters’ moods change.