Although Sydney Was Not Feeling Very Well, She Went to Her

Although Sydney was not feeling very well, she went to her favorite Chinese restaurant for lunch.After eating the food, she became very sick.Upon going to the doctor, she found out that it was a stomach virus that had made her sick, not the food.However, the next time she went to the Chinese restaurant and smelled the food, she immediately felt nauseous.In this story, the unconditioned response (UR) was

A) the smell of the Chinese food.
B) the stomach virus.
C) getting sick due to the stomach virus.
D) getting sick to the smell of the Chinese food.