Final answer:
Ron's great performance in his first Quidditch game was due to the belief that he had ingested liquid luck, given by Harry as a placebo, but it was actually his own skills and confidence that led to his success.
Step-by-step explanation:
The reason for Ron's great performance in his first Quidditch game is C) He was inspired by Hermione. In the Harry Potter series, specifically in 'Harry Potter and the Half-Blood Prince', Ron Weasley believes he has ingested liquid luck (Felix Felicis) thanks to Harry pretendiing to slip it into his drink.
This placebo effect gives him the confidence to perform well during the game. However, it was really just Ron's own skills and the belief that he had luck on his side that resulted in his great performance. The other options, such as a luck potion, special broomstick, or good luck charm are not related to this instance in the books.