Why was the Gadsden Purchase necessary in expanding the railroad system of the United States?

Responses
A The territory provided the necessary iron to build the railroadsThe territory provided the necessary iron to build the railroads
B It had an abundance of the water necessary for railroad stopsIt had an abundance of the water necessary for railroad stops
C It provided a route that avoided the Rocky MountainsIt provided a route that avoided the Rocky Mountains
D The area was free of Native Americans

C It provided a route that avoided the Rocky Mountains

By acquiring the Gadsden Purchase, the United States gained a more desirable route for the construction of the railroad system, as it allowed for a route that avoided the difficult terrain of the Rocky Mountains. This made the expansion of the railroad system more feasible and efficient.