Answer:
C. enabled trade to most parts of the country
Step-by-step explanation:
In the United States, railroads began to the built in the early nineteenth century, and by the late nineteenth century, most of the country was connected by a extensive railroad network.
This network allowed trade to flourished in most of the country. All kinds of goods could be shipped back and forth between the different regions, for example, meat from Texas to Northeast, or Manufactured Goods from Ohio and Michigan to California.