Final answer:
The requirement for written listings comes from the Statute of Frauds, which aims to prevent fraud in certain contract types by requiring a written agreement.
Step-by-step explanation:
The requirement that all listings be in writing is mandated by d. The Statute of Frauds. The Statute of Frauds is a legal concept that requires certain types of contracts, including those for the sale of land or real estate, to be in written form to be legally enforceable. This legal principle is designed to prevent fraud and misunderstanding by ensuring there is a clear and concrete record of the agreement. It does not stem from the Arizona Constitution, the Statute of Limitations, or the Law of Agency, which have different legal functions and implications.