Benjamin entered a pizza-eating contest when he was in college. he finished five large pizzas by himself, but he felt nauseated and threw up a few hours later. for several years, the sight and smell of pizza made him feel sick. in this scenario, benjamin's aversion toward pizza occurred through

I believe the correct answer is classical conditioning.
Conditioning has to do with learning new behaviors based on a particular stimulus. In the case above, the stimulus was too many pizzas, and the result was the Benjamin threw up after eating them. Consequently, he 'learned' to become sick every time he saw or smelled pizza because of what happened when he ate too many.