The correct answer is C. A mostly rural society to a mostly urban one
Step-by-step explanation:
In terms of population displacement or movement, the biggest change in U.S. societies from the end of the 19th century to most of the 20th century was the migration from rural areas to urban areas. Indeed, before this time most of the population lived in rural areas or near small villages but due to the expansion of industrialization in cities or near to them and a decline in agriculture, thousands of people moved to urban areas and settle in them. This also contributed to the rapid growth of cities and this completely change the distribution of the population in urban vs rural areas.