Whenever Kim and Russ Become Romantic, They Always Play Ravel's

Multiple Choice

Whenever Kim and Russ become romantic, they always play Ravel's classic instrumental work Boléro in the background. One day, as Kim is walking past a music appreciation class, she realizes that the class is listening to Ravel's Boléro. As she continues to walk down the hall, she smiles to herself as intimate thoughts of Russ cross her mind. Which of the following best represents the unconditioned stimulus in this example?

A) the sound of Ravel's Boléro
B) intimate physical contact with her partner
C) the sight of the musical appreciation classroom
D) sexual arousal in response to the classical work Boléro