The correct answer is:
A. It created the process for admitting states and expanding the country.
The Northwest Ordinance of 1787 established a framework for the governance of the Northwest Territory and set a significant precedent for the admission of new states into the Union, which was crucial for the westward expansion of the United States. It also included important provisions related to education, civil liberties, and the prohibition of slavery in the territory, making it a foundational document in American history.