The Introduction of Steamboats

The introduction of steamboats

A) led to dramatic declines in the price of upstream transport.
B) led to moderate declines in the price of downstream transport.
C) is the primary reason for falling transportation costs in the early 1800s.
D) led to an initial decrease in transport costs that continued to fall due to learning by doing and the construction of lighter boats with increased capacity.
E) All of the above.