Answer:
Aversion therapy
Step-by-step explanation:
Aversion therapy is a kind of therapy used to stopped undesired behaviors. This therapy involves pairing an unwanted behavior in a repeating manner with discomfort produced by this behavior. After some repetitions, the undesired conduct will stop.
In this example, every time Leo opens his cigarette case or uses his lighter he he gets a painful electric shock. He must use his own lighter if he wants to smoke. Eventually, Leo loses his desire to smoke. We can see that the undesired behavior of smoking has been paired by the discomfort created by the electric shock. Therefore Leo losing his desire to smoke is thanks to aversion therapy.