What reason does Hazel have for not wanting to ride Waverly?

Hazel's reluctance to ride Waverly stems from a past experience where she froze up during a show. This previous incident likely left her feeling anxious or fearful about competing again, especially on Waverly, which may remind her of that moment. Such a traumatic experience can have a lasting impact, making her apprehensive about putting herself in a similar situation. This context adds depth to her character, illustrating how past events can influence present behavior and decisions.

The other options, while they could be plausible reasons, do not capture the emotional weight of a past failure that affects her current choices. Being busy with school or preferring to compete at home are factors that may affect many riders, but they lack the personal significance of a fear linked to a previous experience. Similarly, her personal feelings towards other riders would not inherently prevent her from wanting to ride but may influence her competitive drive.