In a conditioning experiment, a sound is paired with a brief puff of air to the eye of the rabbit. After several pairings, the rabbit ultimately blinks its eye when it hears the sound. Which of the following is true?
a. The blinking of the eye serves as stimulus.
b. The puff of air serves as the unconditioned stimulus.
c. The puff of air serves as the conditioned stimulus.
d. The blinking of the eye serves as the conditioned stimulus.
e. The air puff is a discriminative stimulus.