Concept:Operant conditioning is a learning theory where behavior is shaped by rewards and punishments. It was developed by B.F. Skinner.Explanation:Skinner’s theory focuses on voluntary responses and their consequences. He used experiments with animals to show that reinforcing desired actions increases their likelihood. The learner emits a response, and reinforcement strengthens it. This process gradually conditions the learner to perform the desired behavior. Other theorists like Thorndike (stimulus-response) and Hull (drive reduction) proposed different learning models. Operant conditioning is specifically Skinner’s work.Answer:D. Skinner