Name the three main mountain ranges in the United States.
The three main mountain ranges in the United States are the Rocky Mountains, the Appalachian Mountains, and the Sierra Nevada Mountains.
Complete the following task based on the instruction and optional input provided.### Instruction:
Name the three main mountain ranges in the United States.

### Output:
The three main mountain ranges in the United States are the Rocky Mountains, the Appalachian Mountains, and the Sierra Nevada Mountains.