Which of these sentences doesn't make sense?
Options:
- Sentence A: "He is writing a letter to a friend."
- Sentence B: "He is laughing a letter to a friend."

Hmmm, let me think. I want to lay out the solution in details.

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 letter can be laughed at, but it must be written. The answer is Sentence B.