Final answer:
John's experience of associating freshly baked cookies with his grandmother's image is an example of classical conditioning, where the cookies have become a conditioned stimulus connected to the unconditioned stimulus of his grandmother's presence.
Step-by-step explanation:
The example of John associating the taste of freshly baked cookies with the image of his grandmother best illustrates the concept of classical conditioning. Classical conditioning is a learning process that occurs through associations between an environmental stimulus and a naturally occurring stimulus. In this case, the freshly baked cookies (conditioned stimulus) have become associated with the image of his grandmother (unconditioned stimulus), creating a conditioned response which is the mental image of his grandmother being triggered by the taste or aroma of cookies.