Final answer:
Price discrimination requires the prevention of resale.
Step-by-step explanation:
Price discrimination is the practice of charging different prices to different groups of buyers for the same product or service. The necessary condition for price discrimination is the prevention of resale. By preventing buyers from reselling the product, a business can charge different prices to different groups based on their willingness to pay. This allows the business to maximize its profits by extracting more value from each group of buyers.