Answer:
The answer is D. To produce extinction Pavlov paired the bell with the absence of food.
Step-by-step explanation:
In psychology, the term extinction is used to describe when a certain behavior decreases or disappears. In classical conditioning, Pavlov produced extinction of the salivation of the dog after the response was conditioned, by not providing the unconditioned stimulus, that was the food.
Once he had paired the sound of the bell with the food and the salivation, he stopped giving food and eventually, the salivation response became extinct.