In the 1800s, what route did pioneers follow to settle the pacific coast?

Pioneers followed the California Trail to settle the Pacific Coast in the 1800s.

The California Trail was one of the main routes of migration towards the West of the United States in the mid-nineteenth century, which started from the state of Missouri and went to California. It was used by more than 250,000 settlers and then gold seekers, to get to found farms and the gold fields of California, from the early 1840s to the construction of railroad tracks, in late 1860.

The original route had many branches and traveled more than eight thousand kilometers. About 1,600 km of the route through the Great Basin are still conserved and have been declared as "California National Historical Trail", as historical evidence of the great mass migration to the West, and are managed by the National Park Service.

i would say b. research typically uses a variety of sources