Private ownership and free markets.
(You're welcome!)
The answer is: C
This is because the graph indicates the sharp decline of the rural population, due to in large part to the increase in urbanization and the ever-growing industrialization of the United States throughout the decades.
As such we can analyze that, as the years go by the population trends to move to urban areas in place of rural ones.
The population of the city of dublin mostly did in this timeframe
<span>The Americas were the last (well, second-to-last if you count Antarctica) continents to be inhabited by early humans. Archaeologists estimate that people entered North America by crossing over the Bering Strait, which back then was a wide swath of land, about 15,000 years ago.</span>