Answer:
The correct answer would be option A, Unconditioned Response. In classical conditioning, the Unconditioned Response is an unlearned reaction to a given stimulus.
Explanation:
Classical Conditioning is basically a learning process. In this process, a biological potent stimulus is paired with the stimulus which was previously neutral.
In classical conditioning, there comes the conditioned or unconditioned responses. An unconditioned response is an unlearned response. This unconditioned response occurs in reaction to the unconditioned stimulus. For example if a person feels the smell of food, then smell of food is an unconditioned stimulus, and if the person feels hunger due to that smell of food, then the hunger is an unlearned response to the unconditioned stimulus.
Similarly, in this question, if you have an allergy to pollen and you sneeze, then sneezing is an unlearned response to the pollen which is a unconditioned stimulus.