Final answer:
A brokerage firm representing a seller as a single agent can work with the buyer in the same transaction as a transaction broker, providing limited representation without fiduciary duty to either party.
Therefore, option C is correct.
Step-by-step explanation:
When a brokerage firm represents a seller as a single agent in a transaction, and they wish to work with the buyer within the same transaction, the brokerage can do so as a transaction broker. In a transaction broker relationship, the brokerage provides limited representation to both the buyer and the seller without a fiduciary duty to either party. This is different from a single agent relationship, where the brokerage owes fiduciary duties to the seller, or working in a no brokerage relationship, where the brokerage does not represent either party. Brokerage firms must ensure that both buyers and sellers are well-informed about market conditions as stated in point 4 and can engage freely in the market as stated in point 5.