Freight costs were reduced to 10% of what they had been because of

A．The Erie Canal connected Lake Erie and the Hudson River.
B．Economists are of the opinion that places where farming is done are good for making rawmaterials into finished goods.
C．Wagons drawn by horses and oxen soon proved to be better and cheaper than canal transportation.
D．The coming of the railroads caused New York to become less important as a shipping center.

A．is mentally ill.
B．performs an insignficant proportion of American business.
C．will not have the regrets that many "normal" people face at middle-age.
D．suffers from low serf-esteem.