Answer: C. They gave them lots of land to build the tracks on.
Explanation:
Option A is incorrect because railroads didn´t need governmental permission to pay more money to their workers. Option B is incorrect because raising taxes would not have helped them made more money. And slave labor from the American South was not used specifically for this purpose. It was by granting public domain land to the railroads that the United States government encouraged the construction of railroads between 1850 and 1871 because there was a strong interest in building a transportation system that could connect the East and West Coast with the rest of the country.