Answer:
The answer is food (Option A)
Explanation:
To begin with, an unconditioned response is a type of response that is not learned. This kind of response occurs as a natural reaction to the unconditioned stimulus (a stimulus that automatically and naturally triggers or causes response).
For example, if the aroma emanating from good food is the unconditioned stimulus, then salivation and the sudden feeling of hunger is a natural way to respond to such stimulus.