After Pavlov's dogs became conditioned to salivate at the sound of the bell, he experimented with ringing the bell and then failing to present the dogs with any food right away. Soon they stopped salivating to the sound of the bell. This represents the process called __________

A) acquisition.
B) testing.
C) extinction.
D) spontaneous recovery.

Extinction is the process of gradually eliminating a learned response by repeatedly presenting the conditioned stimulus without the unconditioned stimulus. In this case, Pavlov rang the bell (conditioned stimulus) without presenting any food (unconditioned stimulus), resulting in the dogs eventually stopping their conditioned response (salivating in response to the bell).