The correct answer is extinction.
Extinction refers to a concept from the psychologist, Ivan Pavlov's theory of classical conditioning. It is the process whereby, when a conditioned stimulus (CS) is no longer followed by an unconditioned stimulus (UCS), the conditioned response (CR) stops occurring or becomes 'extinct'. In this instance,when the packet of meat powder (CS) was not followed by feeding it to the dog (UCS), the dog stopped salivating (CR).