Pavlov Conditioned a Dog to Salivate at a Bell Sound

Multiple Choice

Pavlov conditioned a dog to salivate at a bell sound that was paired with a meat stimulus.After the CS-UCS linkage was strongly established,Pavlov then presented the dog with several flashes of a light followed by the bell sound.After a few days,when the light flashes were presented by themselves,the dog salivated.This is an example of

A) spontaneous recovery.
B) higher-order conditioning.
C) stimulus generalization.
D) extinction.