Final answer:
The conditioned response (CR) in this experiment is fear, as the mouse has learned to associate the 5,000 Hz sound with receiving a shock.
Step-by-step explanation:
The conditioned response (CR) in this experiment is the Fear that the mouse experiences whenever a 5,000 Hz sound is produced. The mouse has associatively learned to associate the sound with the unpleasant experience of receiving a shock, which elicits fear. Fear is a natural response that occurs in animals when they perceive a potential threat or danger, and in this case, the mouse has learned to associate the 5,000 Hz sound with the shock and therefore exhibits fear as a response.