Answer:
D) "Many of you will live to see the day, perhaps fifty years from now, when there will be 400 million Americans, four-fifths of them in urban areas."
Step-by-step explanation:
it mentions urban areas meanwhile the others dont so it supports the idea of urban areas.
What is an urban area?
A human community with a high population density and built environment infrastructure is referred to as an urban area, built-up area, or urban agglomeration. Researchers classify urban regions, which are the result of urbanization, as cities, towns, conurbations, or suburbs.