A property was listed with a broker, but the owners advertising the property found a buyer and negotiated the sale themselves. After the closing, the owners paid a full commission to the broker. The broker must have had

An open listing allows the property owner to sell the property themselves or to list it with multiple brokers. Only the broker who successfully sells the property receives a commission. Since the owners in this scenario paid a full commission after selling the property themselves, an open listing does not apply.

An exclusive agency listing permits the owner to sell the property independently while granting one broker the right to sell it. If the owner sells the property themselves, they do not owe the broker a commission. Given that a full commission was paid to the broker after the sale, this option is incorrect.

A net listing is an arrangement where the broker earns any amount above a specified net price to the seller. While this type of listing can involve commission payments, it is not guaranteed that the broker would receive a commission in every case, especially if the owner sells the property themselves. Therefore, this does not fit the scenario.