An insurer markets its products by soliciting customers by mass media advertising and mail without using the services of a producer. Which of these marketing systems does the insurer utilize?

The insurer is utilizing a Direct Response marketing system because this method involves reaching out to potential customers directly through mass media advertising and mail campaigns without the involvement of agents or producers. In this system, the company communicates its insurance products straight to consumers, allowing them to interact and make purchasing decisions without intermediary representation.

This approach contrasts with an Agency System, where agents represent the insurer and facilitate the selling process. An Exclusive Agent System also involves agents, but specifically those who are contracted to represent only one insurance company. Similarly, an Independent Agent System consists of agents who can represent multiple insurers but still rely on the agent's influence to make sales. The absence of agents in the Direct Response method is what distinctly qualifies it as the correct choice in this context.