Decide which part of the plot each event occurs in.
Arianna gets her results back, and she has placed into Spanish 1. 
✔ exposition
Arianna discusses the results with the principal, who does not believe Arianna. 
✔ rising action
Arianna insists on seeing her test and the answer key. 
✔ climax
Arianna discovers a mistake in the answer key, not her own test. 
✔ falling action / resolution