Historians are in general agreement that (a) railroads opened the cou

Historians are in general agreement that

(a) railroads opened the country and were built at great risk ahead of demand, gambling on the future.
(b) railroads sharply cut down transportation costs, linking the country together in all directions
and spurring the nation’s growth far in advance of anything that might otherwise have been achieved.
(c) railroads were the single innovation of the 19th century that created a great leap forward
in terms of American economic growth.
(d) none of the above are true.

ANSWER

(d)