The correct option is C
The first Europeans to explore this region were the Castilians, and later, the British founded the first settlements. The region was originally part of a greater called Oregon Country, a territory disputed between the Americans and the British between the decades of 1810 and 1840. In 1846, the Treaty of Oregon states that all the lands south of the 49th parallel of the Oregon Country would pass to the control of the United States (with the exception of Vancouver Island). Until 1859, Washington was part of the territory of Oregon, created from the American part of the Oregon Country. In 1859, the territory of Washington was created, which was named in homage to George Washington.