The correct answer is A) land prices decreased.
The railroads changed the economy in all of the following ways except "land prices decreased."
The Pacific Railway Act of 1862 allowed the construction of the transcontinental railroad that would unite the East and the West of the United States. The Union Pacific Company and the Central Pacific Company were the ones chosen to build the railroads. The creation of these railroads changed the economy of the United States. Lumbering grew as a result of increasing populations in towns. New factories were established to manufacture materials needed for railroads and agriculture activities expanded. But what did not happen was that land prices decreased. To the opposite, they increased due to the demand for it.