The correct answer is the following.
Although the question is incomplete because it does not include the map and the texts referred, we can comment on the following.
We are talking about the states from the south of the country across the southwestern and southern states such as Florida, Georgia, Alabama, Louisiana, Texas, and California.
The growth of this important region of the United States began during World War II because some military industries and weapon factories moved to this Sun Belt area, creating many jobs for the citizens. By the 1970s, many immigrants from México and Central American gave another economic dimensión to this area due to their work in the farm fields. They established there and created an impressive economic movement between the border Mexican states.