Which of the following is an example of positive reinforcement? A. Giving a learner a sticker for raising their hand before speaking, and they never raise their hand again.
B. Taking away a sticker for not raising their hand before speaking, and they continue to not raise their hand before speaking.
C. Taking away a sticker for not raising their hand before speaking, and they quit participating in class discussions.
D. Giving a learner a sticker for raising their hand before speaking, and they continue to raise their hand.