Should I use 'that' 'which' or 'who' in this sentence?

Boys don't play with dolls that they know for a long time, unless they see another boys playing with them.

Well it means that boys sometimes boys are not interested in a girl they know for a while until they discover the girl has someone.

In this sentence, dolls is a symbol for girls. I'm a bit confused if I should use that, which or who?

(by the way, should use 'until' instead of 'unless'?)

Solution 1:

Use that where it refers to an object, and is a restrictive clause (meaning, if you left the word out of the sentence, the meaning of the sentence would change):

I want the hat that has the giant flower in the band.

Use which where it refers to an object, and is a non-restrictive clause (meaning, if you left the word out of the sentence, the meaning of the sentence wouldn't change):

I have a lovely new hat, which has a giant flower in the band.

Use who where you are referring to a person:

I saw a lady who was wearing a lovely new hat.

I'm having trouble answering your question more directly, because I can't really understand your sentence. I'm not sure whether you are referring to dolls in the sense of toys (in which case you should use that because "know for a long time" is a restrictive clause), or in the slang sense for women (in which case it should be who, and I would probably recommend that you find a less sexist term!).