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: Psychiatry
Behaviour therapy to change maladaptive behaviour using the response as reinforcer uses the principles of- 
Select and explain. 
A. Classical conditioning, B. Modeling, C. Social learing, D. Operant conditioning
D: Operant conditioning
Answer: D: Operant conditioning 
Explanation: Reinforcement is used in operant conditioning.