Answer:
D. classical conditioning
Step-by-step explanation:
Classical conditioning is a term proposed by one of the most influential psychologist's names Ivan Pavlov while researching with dogs and he has described classical conditioning as a learning theory that encompasses a stimulus and a response.
Classical conditioning in psychology referred to as the process in which a particular stimulus gives rise to a learned response when connected with a neutral stimulus.
In the question above, the given statement signifies the classical conditioning.