The best example of classical conditioning is:
"Jennifer was in a terrible car accident last year. Now, even the sound of screeching tires can make her anxious and afraid."
This scenario demonstrates classical conditioning because Jennifer has developed a fear response (anxiety and fear) to a specific stimulus (the sound of screeching tires) as a result of her previous experience in a car accident, which is a classic example of how an emotional response can be conditioned through association with a traumatic event.