What characterizes a situation where an agent is serving a seller while simultaneously engaged with a buyer?

The situation where an agent represents both a seller and a buyer simultaneously is characterized as dual agency. In dual agency, the agent has a fiduciary duty to both parties, meaning they must navigate the transaction carefully to ensure that both the seller and the buyer's interests are represented fairly and equitably. This arrangement requires full disclosure, and consent is typically necessary from both parties. By engaging in dual agency, the agent must balance the competing interests and transactional goals of both clients without favoring one over the other.

In contrast, exclusive agency refers to a type of listing agreement where the seller retains one agent to sell their property but may still find a buyer independently. Sub-agency involves a situation where one agent represents another agent's principal, usually in transactions where the original agent does not have a direct relationship with the client. Buyer representation specifically deals with agents who exclusively represent buyers in their search for property, which does not include a seller's representation in the transaction. These distinctions highlight why dual agency is the correct answer for the characteristics described in the question.