The market that generally involves pure competition is the market for corn. Explanation:

• Pure competition is characterized by many sellers offering identical or very similar products, with free entry and exit in the market, and price-taking behavior.
• The corn market fits this description because it typically involves many producers supplying a standardized agricultural commodity.
• In contrast, the cola market is an oligopoly dominated by a few large companies like Coca-Cola and Pepsi.
• The jeans market exhibits monopolistic competition due to product differentiation and branding.
• The ice cream market, while competitive, often involves many small producers but is not the classic example of pure competition as corn is.