Which of the following actions falls under the category of limiting market control?

Limiting market control refers to actions that prevent companies from dominating the market or gaining an unfair advantage over competitors. Controlling product distribution channels can limit market control by ensuring a wider distribution reach, which helps new entrants or smaller firms compete more effectively. This action can prevent monopolistic practices by allowing various products from different companies to be available to consumers, thereby fostering competition and improving market dynamics.

On the other hand, offering free samples to consumers typically serves as a promotional strategy aimed at increasing short-term sales or product awareness rather than limiting market control. Collaborating on a new marketing campaign might bolster a company's market presence without directly addressing market dominance. Increasing staff wages to retain talent is primarily a human resources strategy focused on workforce stability and does not directly influence market control dynamics. Thus, controlling product distribution channels is a pertinent example of an action that contributes to limiting market control by promoting competition and accessibility in the market.