F: I'm going to sleep after turning off the lights. ,M: I'm going to take a walk first.
(A) F: Although you don't go for a walk, I'll go to bed after taking a walk. (B) F: But I prefer go to sleep once turning off the lights. (C) F: I am really sorry, I did not catch that. Would you slow down, please? (D) F: Since you're not going for a walk, let's go to bed before turning off the lights.
B