Diana, Who Is 4 Years Old, Has Been Biting and Scratching

Diana, who is 4 years old, has been biting and scratching her playmates in preschool. What might you suspect as a possible cause of this behavior?

A) Her parents may be experiencing a lot of conflict in their marital relationship.
B) Her parents' relationship is probably not related to her behavior.
C) Her parents probably also had such behavior problems when they were children.
D) Diana's parents probably aren't getting enough sleep, and thus they are not giving her enough attention at home.