The use of coin - operated machines to sell goods is a form of

Explanation

Retailing refers to the process of selling goods directly to the final consumer. When goods are sold through coin-operated machines, it is a form of retailing because the consumer can directly purchase the product without the need for any personal interaction with a salesperson. Instead, they simply insert coins into the machine and receive the product.

Wholesaling, on the other hand, refers to the process of selling goods in large quantities to retailers or other businesses. This does not involve coin-operated machines.

Personal selling involves a salesperson directly interacting with the customer to sell a product or service. This is different from using coin-operated machines.

Mail-order selling involves purchasing goods through mail or online orders and having them delivered to the customer's address. This is also different from using coin-operated machines.

In summary, the use of coin-operated machines to sell goods is a form of retailing, which is the correct answer to the question.