Polly Works as a Bartender

Polly works as a bartender.A few people wave money at her so that she will serve them first.She finds this to be rude and,so,either ignores them or serves them last.People realize that Polly serves the people who wait politely first,and much of the rude behavior stops.Polly used the model of

A) positive reinforcement.
B) negative reinforcement.
C) variable ratio reinforcement.
D) extinction.
E) shaping.