It sure isn't D. One of the reasons the South had trouble during the civil war is that she didn't have enough rail lines. Horses did much of the work the rails did.
The rails existed in 1865. There were lots of them. Trouble was they were mostly in the North.
The large population centers were largely in the east. Shear numbers would make rails feasible. Answer
The West did oppose the rails to some extent, but industry (like cattle and mining) wanted more rails. Most of the time the opposition came for economic reasons.
economic The first and most important point is that the Civil War was expensive. In 1860 the U.S. national debt was $65 million.
Political The Civil war had profound effects on the the United States and the Confederacy in economic, political, and social. The war had different effects depending on the region which can be divided by effect on the south, north, and west.
Earlier in the 1700s, the French & Indian war happened in which Great Britain was involved in. They made taxes so they could pay all of their soldiers for fighting in the war.