This territory was received as a part of the peace settlement with Britain at the end of the Revolutionary War. Oregon Territory
Ceded by britain
Treaty of Paris
Spanish Cession

Treaty of Paris

Explanation:

Perhaps as important as U.S. independence, the Treaty of Paris also established generous boundaries for the new nation. As part of the agreement, the British ceded a vast area known as the Northwest Territory to the United States.

when in doubt choose c

it's what my teacher told my class when we were going into psats