Here is the full question: Tina has a heavy class load and is spending a lot of time studying, to the dismay of her beloved dog, bobo. When bobo walks over and puts his chin on Tina's leg, she lets him and gives him a treat from the bag she keeps in her desk drawer. As a consequence, he continues walking over and putting his chin on Tina's leg. Tina has used _____.
The answer is positive reinforcement.
