The correct answer is D. 1836
Explanation:
The Oregon Trail was a route from the Missouri River to the valleys of Oregon, this route was around 3500 kilometers and was a key trading route. This trail was first mapped in 1804, and later used by fur traders and other traders from 1811 to 1840, however during the first years the route could only be crossed on foot or by horseback. In 1836, the first wagon traveled along the Oregon Trail which increased the use of the trail as settlers, miners, ranchers, farmers, migrants and others began using the Oregon Trail. Thus, pioneers, Henry Spalding, and Marcus Whitman were the first who traveled along the Oregon Trail by wagons in 1836.
