The correct answer is A) Clean Air Act.
In the 1950s and early 1960s, an expansion in the highway system the swelling of suburban communities and increased industrial output caused congress to pass the Clean Air Act.
The construction of the highway system in the United States improved communications in the country, connecting many parts of the US through modern highways. This increased the number of cars sold in the country but it generated another big issue: air pollution. That is why the US federal government had to pass the Clean Air Act of 1970 to lower the levels of ozone and other toxic pollutants.