Animal Crossing - Different Question, not looking for friend codes, etc.

Hey, I'm just looking for help with something that isn't in the guide, or any of the walkthroughs I've read.

As I'm selling things to Tom Nook, he keeps sighing, and then asks me about his clothes, regardless of what answer I pick, he keeps doing it, and I can't figure out why. Can anyone help me out?

----Mods: Please, before you close this thread and refer me to another one, please note that the thread that you keep referring people to for these posts was already closed by another mod; it seems kind of useless...