Dylan tends to do his best skateboarding in torunaments when he's excited, rather than overly nervous or too calm. his experience can best be explained by

The correct answer is:

Sport-related anxiety.

Explanation:

According to the study Sport-related anxiety: current insights  conducted by

Jessica L Ford, Kenneth Ildefonso, Megan L Jones, and Monna Arvinen from the University of Wisconsin published at the Journal of Sports Medicine— An Open Access, there is a great influence of anxiety over the performance in sports, especially those of extreme impact. Before, it was normally thought that the stress and anxiety produced when performing competition sports could affect the results. However, after this study it was confirmed that when using some effective psychological strategies in the performance of extreme sports is really beneficial for competitions. Besides, it has also been confirmed that anxiety has a positive influence in the prevention of injuries and that it also contributes to a better recovery after an injury.

i am pretty sure it is d.