The Expansion of the Railroads Created Which of the Following

The expansion of the railroads created which of the following shifts in the Northern economy?

A) The Northern economy overtook the Southern by 1850.
B) The canal systems became obsolete, creating debt.
C) The North went from trading with the South to trading with the West.
D) Skilled labor began moving west, creating vast shortages.
E) Banks began to be owned exclusively by railroad companies.