Answer:
B. unconditioned
Step-by-step explanation:
Suppose that the smell of food is an unconditioned stimulus and a feeling of hunger is the unconditioned response. Now, imagine that when you smelled a wonderful lasagna, you also heard the sound of a whistle.
The whistle is not related to the smell of the food, but if the sound of the whistle is paired several times with the smell, the sound ends up triggering the conditioned response. In this case, the whistle sound is the conditioned stimulus.
In summary, we can say that the unconditioned stimulus is capable of generating an unconditioned response, but in classical conditioning, the conditioned stimulus is a previously neutral stimulus that, after becoming associated with the unconditioned stimulus, eventually triggers a conditioned response.