Sally was in the kitchen trying to get dinner ready for the family; Zach, her two-year old was holding on to her skirt and whining for another cookie. She had already given him two, and his determination to get a third was clearly evident. She knew her best course was to ignore him, since she had explained (several times) that two was the limit. This is an example of:
B) Negative Reinforcement
The correct answer is "A) Extinction".