A small broker committee sets a single non-negotiable commission rate for every seller. This marketing plan is an example of

The term "apostle" typically refers to a messenger or advocate, particularly in a religious context. In marketing, it might describe a passionate supporter of a brand or product. However, it does not relate to the concept of setting commission rates or controlling pricing in a market. Therefore, it is not applicable in this context.

Market allocation refers to an agreement between competitors to divide markets among themselves, either by geographical area or type of customer. While it involves anti-competitive practices similar to price-fixing, it does not directly relate to setting a uniform commission rate for all sellers, which is the key focus of this question.

Consumer protection encompasses laws and regulations designed to ensure fair trade, competition, and the free flow of truthful information in the marketplace. While the intent might be to protect consumers, the imposition of a non-negotiable commission rate is more indicative of anti-competitive behavior rather than a genuine effort to protect consumer interests.