________ carriers typically move commodities over large distances at lower costs per unit shipped.

A) Air
B) Truck
C) Rail
D) Package

Rail carriers are known for their ability to move commodities over large distances, taking advantage of the economies of scale to offer lower costs per unit shipped. Air carriers are typically more expensive, while truck carriers may not be able to haul as much volume as trains. Package carriers are geared towards smaller shipments and do not specialize in moving large quantities over long distances.