The correct answer is England.
During the middle of the 19th century, the Oregon territory was jointly occupied by the United States and England. This joint occupation became an issue during the United States era of westward expansion. The United States was trying to take over as much land as possible in the North American continent, causing issues in the Oregon territory. The United States came close to a third war with Britain over this territory. However, US President James K Polk and the English government were able to negotiate a deal. The United States would receive all territory south of the 49th parallel while England would control everything north of this parallel. This helped to establish the modern day border between Oregon and Canada.