Answer :
Most families that settled on the Plains started farms in Colorado, New Mexico Territory, and Kansas. Plains is a city in the state of Kansa in United States. The original name of Plains is West Plains which has a total area of 1 square mile.
I believe the answer is:B. Nebraska, Kansas, and South Dakota.
These states had a consistent warm weather along with soils that are high in nutrition. This make them become a perfect environment for the farmers to grow various crops that are popular in the market. Because of this economic benefits, most farmers family settled in these area.