Answer:
The answer is the arousal.
Explanation:
In classical conditioning, a conditioned stimulus (the beer) is associated with an unconditioned stimulus (the woman), which produces an unconditioned response (arousal).
This idea was demonstrated by Russian scientist Ivan Pavlov. In a famous experiment, he would ring a bell shortly before feeding a dog. The dog would soon start salivating at the sound of the bell, as it associated it with the food.
