Stanley was diagnosed with lymphoma and had to undergo several months of chemotherapy. During this time he would become very nauseated as a side effect, and unintentionally came to associate that nausea with his favorite grilled cheese sandwich. Now, years later, even thinking about a grilled cheese sandwich makes him sick. In this example, Stanley's nauseous reaction to a grilled cheese sandwich is the . a. unconditioned stimulus
b. unconditioned response
c. conditioned stimulus
d. conditioned response