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
Praise, positive facial expression, shaking hands with the patient comes under: 
Select and explain. 
A. Positive reinforcer, B. Negative reinforcer, C. Social reinforces, D. Material reinforces
C: Social reinforces
Answer: C: Social reinforces 
Explanation: Praise, positive facial expressions, shaking hands with the patient are the social reinforces.