John was taught by his teacher to say, "hello" when greeting people. now when he meets people he not only says "hello," but also says: "hi," "good to see you" and "hey there." john’s behavior change is an example of:

The answer is response generalisation.

Explanation:

This occurs when a target response (i.e. the desired behaviour) spreads to other similar variations. For example, a child might be taught to cut a piece of food with a knife, but then starts doing it with a fork.

Response generalisation is independent of place and time. An example is learning to wash your hands before eating, which may occur at school, home and other places.

i would pick a. i think this is more of a personal question though.

a dellusion is athing where your mind sees stuff