How did this map change following the Treaty of Washington in 1846? ( 10 points) a
The Oregon Country was divided between Britain and the United States at the 49th Parallel.

b
The Oregon Country was split into the Washington and Oregon Territories using the 49th Parallel as the new boundary.

c
The boundary between the Oregon Country and Mexico was shifted from the 42nd Parallel to the Oregon Trail route.

d
The portion of the Oregon Country below the 49th Parallel became part of Mexico, while the portion above the 49th Parallel became part of Great Britain.