It began as an unconnected series of trails used by American Indians. Fur Traders expanded the route to transport pelts to trading posts and rendezvous. In the 1830s missionaries followed the still faint trail along the Platte River and the Snake to establish church connections in the Northwest. A combination of economic and political events in the 1840s converged to start a large scale migration west on what was then known as "The Oregon Road." Joel Walker is credited as the first settler to make the complete trip with a family, in 1840. Large scale migration started in 1843, when a wagon train of over 800 people with 120 wagons and 5,000 cattle made the five month journey. In 1847 Mormons escaping persecution headed toward Salt Lake, and the discovery of gold in California in 1848 sent a wave of fortune seekers west. Military posts, trading posts, shortcuts, and spur roads sprang off the Oregon Trail over the next three decades. —Department of the Interior
Use the passage to answer the question.
Which of the following best summarizes this passage?
A. The Oregon Trail was first used by Mormons fleeing religious persecution.
B. The Oregon Trail grew from small beginnings to a major migration route.
C. The Oregon Trail was made more accessible by missionaries who helped define the route.
D. The Oregon Trail was developed by the military to monitor interactions between Native American groups and settlers.