Option: B. It incorporated nearly 50,000 Mexicans as American
Explanation:
The Southwest became part of the United States in 1848 after the Treaty of Guadalupe Hidalgo. The Southwest region consists of states like Colorado, Arizona, Utah, New Mexico, Texas, and Mexico. The Treaty provided a large part of Mexican territories to go under the United States. Thousands of Mexican became American citizens in these regions. Vast land in the Southwest encouraged settlers to move to begin farming and ranches.
