One Saturday, Clayton Was Sitting at Home When the Telephone

One Saturday, Clayton was sitting at home when the telephone rang. A local company was making promotional calls and told Clayton he had just won a $500 gift certificate. He felt a rush of excitement at the thought of what he could do with $500. Now Clayton finds that whenever he hears a telephone ring, he feels a little surge of excitement. In this example, the conditioned response is the

A) surge of excitement that Clayton feels whenever he hears a telephone ring.
B) ringing of a telephone.
C) news that he had just won a $500 gift certificate.
D) rush of excitement he felt when he won the certificate.