The correct answer is C.
The Northwest Ordinance was issued in 1787 by the Congress of the Confederation of the United States. Its approval meant the creation of the Northwest Territory, the first delimited territory of the US. This territory was located on the West of the Appalachian mountains between the British colonies and the Great Lakes. The Southern border was delimited by the Ohio River, and the Missisipi River conformed the Western one.
Slavery was banned within the Northwest Territory. The Federal government considered expanding through the admission of new states.