Final answer:
The New York State regulation requiring subdividers to file with the Department of State before offering parcels on the installment plan is part of state property law but is not named in the question. Historical ordinances such as the Ordinance of 1784 and 1785 pertain to earlier land policies and should not be confused with contemporary state real estate regulations.
Step-by-step explanation:
The regulation that requires subdividers in New York State to file with the Department of State before offering parcels to buyers on the installment plan is embodied within the New York State Property Law. However, the question seems to be mixing historical land ordinances with current real estate regulations, as the historical context provided references the Ordinance of 1784 and the Ordinance of 1785 which pertain to land practices under the Confederation Congress after the American Revolution. It is important to differentiate historical land policies from modern real estate laws and regulations. Today's regulations would be detailed under state property law or real estate law, which governs the sale and subdivision of land in the contemporary legal framework.
Since the question is likely referring to modern legal requirements rather than historical ordinances, the specific New York State regulation or statute is not explicitly stated here. Typically, such compliance involves ensuring that the subdivider has met all the legal requirements for subdivision and sale of land, including the creation of a detailed offering plan or prospectus that outlines the terms of the sale, financial status of the project, and other required disclosures which are filed with the New York State Department of State before parcels can be offered on an installment plan to buyers.