Of the following two sentences, which one is against common sense?
Options:
- Sentence A: "He watched a leopard race a runner."
- Sentence B: "He watched an athlete race a runner."
 Let's be accurate as possible. So think first.

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
A leopard is much faster than a runner.
The final answer: Sentence A.