After Repeatedly Pairing the Sound of a Bell with Food

Multiple Choice

After repeatedly pairing the sound of a bell with food being placed in a dog's mouth, the sound of the bell alone will make the dog salivate. The dog's salivation to the sound of the bell is called the:

A) unconditioned response (UCR) .
B) conditioned response (CR) .
C) conditioned stimulus (CS) .
D) unconditioned stimulus (UCS) .