Question Options:
A. conditioned stimulus.
B. unconditioned stimulus.
C. unconditioned response.
D. conditioned response.
Answer: The injection in this scenario served as the UNCONDITIONED STIMULUS.
Explanation: Unconditioned stimulus refers to anything external that elicits or influences a physiological or psychological activity or response that occurs unconditionally, naturally, and automatically. An example is your cat running to it's bowl whenever it smells food.