Review Question - QID 108211

A parent-teacher conference is called to discuss the behavior of a 9 year-old boy. According to the boy's teacher, he has become progressively more disruptive during class. When asked to help clean up or read out-loud, he replies with "You're not the boss of me." or "You can't make me." He refuses to participate in gym class, but will play the same games during recess. He gets along with and is well-liked by his peers. His mother reports that her son can "sometimes be difficult," but he is helpful around the house and is very good playing with his 7-year-old sister. What is the most likely diagnosis?