What establishes a single agency relationship?

A single agency relationship is established when a broker acts on behalf of a client, representing their interests in a real estate transaction. In this context, the key element is the authorization granted by the employer (the client) to the broker, allowing the broker to act as their agent. This relationship is built upon a fiduciary duty, meaning the broker must prioritize the client's interests above their own.

This contrasts with other options, such as a broker representing both the seller and the buyer, which typically indicates a dual agency situation where the broker has conflicting interests. A customer opting for no representation does not establish any agency relationship at all, leaving the customer without an advocate. Similarly, a broker acting as a transaction broker facilitates the transaction without a fiduciary relationship, focusing on assisting both parties without allegiance to one over the other. Thus, the correct answer highlights the essential element of client authorization necessary to create a single agency relationship.