Answer the following question, with explanation first. Of the below sentences, which one does *not* make sense?
Options:
- Sentence A: "The river flows up the mountain."
- Sentence B: "The river flows down the mountain."

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 river can't flow against gravity up a mountain.
So, the answer is Sentence A.