Final answer:
Option C: Handelmann Florist buying two cases of flower vases from its regional gardening supplies distributor is the best example of a market exchange.
Step-by-step explanation:
The BEST example of a market exchange from the given options is option C: Handelmann Florist buying two cases of flower vases from its regional gardening supplies distributor.
In a market exchange, goods or services are bought and sold between buyers and sellers. In this example, Handelmann Florist is a firm in the goods market that purchases flower vases from its supplier, which is a regional gardening supplies distributor. This transaction involves the exchange of goods for money.
Other options, such as renewing a membership at a health club (option A), buying a hamburger from a vendor (option B), hiring a company for a promotional contest (option D), or purchasing insurance from an agent (option E), may involve financial transactions, but they do not represent a direct market exchange of goods.