please help me correct the right choice so that the pronouns agree with the antecedents.
1- Each of the horses stood on ( its, their ) hind legs.
2) Neither Bob nor Kevin wore ( his, their ) old clothes.
3) Everybody did ( his, their ) best on the exam.
4) Didn't any of the girls return ( her, their ) books to the library?
5) All of the hikers put ( his, their ) boots on.