Answer:
As city populations increased in the early 1900s, cities
D) grew up and out.
Step-by-step explanation:
From 1980 to 1900 cities populations all over the U.S. increased to 15 million, so they also grew up and out because more spaces were needed to sustain the growth of the population. So they expanded in size and increased their number. Because small cities were created in the surroundings of bigger cities. This provided better prices and the costs of living for workers and their families.