Mitchell hires christina to go from florida to new york and negotiate a contract for his company. he gives her specific instructions on what should be in the contract and a written letter that gives her authority to sign on his behalf. christina books a plane ticket, flies to new york, hires a cab, and successfully negotiates the contract. if christina is paid for the plane ticket and cab fare, as well as meals while in new york, it is most likely under the principal's duty of: