Charity used to really enjoy potato salad, so at a family reunion, she ate a large . unfortunately, the potato salad had not been kept cold, and charity became quite ill after eating it. now she finds that even the sight of potatoes in the grocery store can make her feel sick to her stomach. in this example, the sick feeling charity experiences when she sees potatoes in the grocery store is

a. an unconditioned response.
b. a conditioned response.
c. an unconditioned stimulus.
d. a conditioned stimulus.