Answer:
D: Exposure to aggressive models led to increased aggression in preschool children.
Step-by-step explanation:
Bandura's classic "Bobo doll" study demonstrated that children who were exposed to aggressive models, particularly when they saw adults behaving aggressively toward a Bobo doll, were more likely to display increased aggression themselves when given the opportunity to interact with the same doll. This study provided evidence for the concept of social learning theory, which suggests that people can learn behaviors through observing and imitating the actions of others.