Respuesta :
Answer:
A.Dallasâs population has grown as people have moved from the Rust Belt to the Sun Belt.
Explanation:
Dallas is one of the fastest-growing cities in the United States, and one of the main reasons is that many people have moved from the lagging economies of the Rust Belt, to the more dynamic economic of Dallas, which is located in the Sun Belt.
Because of this growth in population size, and also because Dallas has a very hot climate during most of the year, it has become necessary to find ways to improve the efficiency of energy consumption in the city, like the excerpt in the question explains.