Broker A has a listing agreement to sell Seller B's house. If Seller B rejects an offer and later negotiates directly with the buyer, what duty has Seller B violated?

In this scenario, Seller B has violated the duty of loyalty by bypassing Broker A to negotiate directly with the buyer after having a listing agreement. The duty of loyalty requires the seller to act in the best interests of the broker with whom they have an agreement. By rejecting an offer through the broker and then engaging in direct negotiations with the buyer, Seller B undermines Broker A's role and the exclusivity of the representation.

The listing agreement typically grants the broker the right to market the property, negotiate offers, and facilitate the sale, and part of this relationship is based on trust and loyalty. If Seller B directly negotiates without going through Broker A, it can be seen as acting against the interests of the broker, which the duty of loyalty is designed to protect.

The other duties mentioned, such as duty of care, duty of disclosure, and duty of good faith, while important, do not specifically address this situation where a seller engages in unauthorized negotiation with a buyer after accepting the broker's representation. Thus, the violation of duty of loyalty is the most relevant and accurate choice in this context.