Of the following persons, which one would be required to hold a producer's license?

The requirement for holding a producer's license is primarily tied to the selling and solicitation of insurance policies. The individual involved in soliciting policies of insurance is directly engaging with potential clients to explain, advise, and ultimately sell insurance products. This activity falls under the definition of a producer, which involves engaging in the business of sales and distribution of insurance.

In contrast, an officer of an insurer who does not receive commissions is likely involved in administrative or managerial roles rather than the active selling of insurance. Similarly, a trainer who does not sell insurance or an underwriter, who assesses risk and determines policy terms, do not engage in solicitation or sale, and thus do not need a producer's license. Therefore, only the person who is actively soliciting insurance policies is required to hold a producer's license, as this role involves the direct interaction and transaction of insurance products.