A broker who has listed a property for sale cannot legally

A broker can indeed serve as the seller's agent; this is a primary role of a broker who lists a property. Their responsibilities include marketing the property, negotiating on behalf of the seller, and ensuring all aspects of the sale comply with legal standards. This option does not present a conflict of interest.

While a broker can become a dual agent, this requires full disclosure and consent from both the seller and the buyer. Dual agency is legal in many jurisdictions, although it involves unique challenges in representing both parties. It does not, however, conflict with the broker's ability to list the property.

A broker can represent the buyer, but this typically occurs when the broker is not simultaneously representing the seller for that specific property. However, it is not illegal for a broker to represent buyers; it just needs to be distinct from their role as a seller’s agent.