Answer: [Sentence B]
Question: [Which of these sentences doesn't make sense?
Options:
- Sentence A: "You can lose weight by exercising."
- Sentence B: "You can lose weight by eating junk food."
]
Solution: [Junk food can make you gain weight rather than lose weight.]

Answer: [Sentence B]
Question: [Which of the following sentences is nonsensical?
Options:
- Sentence A: "Sewerage is very important for cities."
- Sentence B: "Sewerage is not important to the city"
]
Solution: [City without sewerage will be unhygienic and hazardous.]

Answer: [Sentence B]

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
Question: [Which of the following sentences is nonsensical?
Options:
- Sentence A: "The last thing you do when you go to the mall is walk out the exit"
- Sentence B: "The first thing you do when you go to the mall is walk out the exit"
]
Solution: [When you exit a place you are leaving so you wouldn't do that the first thing.]