This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': 'Praise, positive facial expression, shaking hands with the patient comes under: \nSelect and explain. \nA. Positive reinforcer, B. Negative reinforcer, C. Social reinforces, D. Material reinforces', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Praise, positive facial expressions, shaking hands with the patient are the social reinforces.', 'role': 'assistant'}]