Of the following, which was an effect of the expansion of railroads across the United States?
A Rapid growth of cities increase in steel prices decrease in interstate trade movement of city dwellers to the suburbs
B Railroads provided rapid transportation of people, raw materials, farm produce, and finished products.
C Many Eastern cities decreased in size as their citizens left for the Midwest.
D The construction of railroads caused a great demand for iron, coal, steel, lumber, and glass, depleting the nation's resouces.