Great Prep School is a private high school with a dress code that stipulates the length of its students’ hair. Harry, who is a Great Prep student, lets his hair grow long during his junior year and the summer preceding his senior year. At the beginning of Harry’s senior year, school officials demand that he cut his hair or be expelled. Harry files a suit against Great Prep. On what contractual grounds might Harry most successfully base his claim? Is the court likely to rule in Harry’s favor on any of these grounds? Why or why not?