After the Civil War,how Did the United States Encourage the Incorporation

After the Civil War,how did the United States encourage the incorporation of its western territories?

A) It encouraged settlers to move to the hinterlands with promises of cheap land for homesteading.
B) It enticed farmers to move west by guaranteeing them profits from producing farm goods to meet American consumers' insatiable demands.
C) It recruited territorial residents into its new national army.
D) It encouraged exploration and development of mineral resources.