I like your hats. Which ones?

[Rachel Adams]

Hello.

In answer to a statement like ''I like your hats'' which question is natural which ones or which one? I think ''which ones''. (I already asked a question about one and ones) However, '''which one'' could be possible in a question ''Which one do you like the most?'' Right?

 

[GoesStation]

The statement doesn't say I like your [singular] hat, so Which [singular] one is not a possible response.

You are correct that "Which one do you like the most?" is possible. You're narrowing down the response; your interlocutor has told you they like all of them, but that doesn't exclude the likelihood that they have a favorite.