An increase in railroad mileage in an area led to great economic growth in that area. The most significant economic growth is in the western states and territories.
Economic growth refers to the increase in the production of goods and services in an economy.
An increase in railroad mileage in an area led to great economic growth in that area between 1870 and 1890, the most significant economic growth is in the western states and territories.
Therefore, C is the correct option.
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