Which of the Following Is an Example of an Agent's

Which of the following is an example of an agent's breach of fiduciary duty to his principal?

A) The agent takes presents from the third party and passes them on to the principal.
B) An agent for the vendor makes a profit on the transaction he negotiated for his vendor above his commission and doesn't tell his principal/vendor.
C) An agent for the vendor collects a commission from the purchaser but told his principal and obtained his consent.
D) An agent discloses to his principal/vendor that he is giving some of his commission to the purchaser to induce the purchaser to sign the contract that the principal/vendor wants.
E) An agent negotiates a higher price than the highest sale price reasonably possible at that time.