In the Cartoon Demonstrating How Emotional Reactions Are Learned Through

In the cartoon demonstrating how emotional reactions are learned through classical conditioning, the animated baby was exposed to a rabbit and then heard a balloon pop.The popping balloon frightened the baby.Eventually, just seeing the rabbit would also produce fear in the baby.Fear of the rabbit was the

A) unconditioned stimulus.
B) conditioned stimulus.
C) unconditioned response.
D) conditioned response.