Final answer:
The best description of the main idea is that mascots can represent products, schools, and sports teams, serving as engaging and entertaining figures.
Step-by-step explanation:
The sentence that best describes the main idea of the paragraph provided is: C. There can be mascots for products, schools, and sports teams. This sentence captures the essence of the paragraph, which explains that mascots are not only used for commercial products like cereal, represented by Tony the Tiger, but also for educational institutions and sports teams to engage and entertain audiences during events. The paragraph also touches on the function of mascots in stirring the crowd's energy and adding fun to the environment at these events.