Final answer:
An express agency is established through a listing contract, where a homeowner and real estate broker agree, often in writing, that the broker will act as the agent in marketing and selling the property.
Step-by-step explanation:
The type of agency relationship created through a listing contract is D. Express agency. An express agency is a relationship where the principal and the agent expressly agree to enter into an agency relationship with each other. This agreement can be in writing or oral, but in real estate, it is typically in writing for legal purposes and clarity. A listing contract, which is a written agreement between a homeowner (the principal) and a real estate broker (the agent), explicitly outlines the terms and conditions under which the broker will market and sell the homeowner’s property.
As such, the broker is the homeowner's agent, having been given express authority to act on the homeowner's behalf in real estate transactions, which is the very definition of express agency. This type of relationship is based on formal terms stated in the contract, making it distinct from implied or other forms of agency relationships.