An animal trainer is conditioning an elephant to startle at the sound of a trombone. Every time she plays the trombone, she then shows the elephant a mouse, which startles the elephant. Eventually, the elephant startles at just the sound of the trombone. However, after playing the trombone 10 more times, without a mouse appearing, the elephant exhibits no response. The lack of a response is an example of:

Extinction

Explanation:

Extinction: In psychology, the term "extinction" is determined as the gradual or slow weakening of a "conditioned response" that tends to result in the decrease or declination in an organism's behavior (animal or human beings). This is often considered as one the important parts in the theory of classical conditioning.

In the question above, the lack of response from the elephant is an example of extinction process as the elephant was no more encountering the mouse after the trombone. So, no association left.

well i'm late but i think its: b, c, and e