How did the demand for more railroads affect the steel industry?
A. The demand for more railroads decreased the need for steel because other materials were used to build new engines.
B. The demand for more railroads decreased the need for steel because iron was used to build new rail lines.
C. The demand for more railroads increased the need for steel that was used to build new rail lines.
D. The demand for more railroads increased the need for steel to build new engines.