Without the ability to see the map you are referring to, I can provide some guidance on the National Road.
The National Road, also known as the Cumberland Road, was one of the first major improved highways in the United States. It began at Cumberland, Maryland, and extended westward, reaching as far as Vandalia, Illinois.
- The statement "The National Road ended in Florida" is incorrect.
- "The National Road stretched across the whole country" is also incorrect as it did not go to the Pacific Ocean or across the entire country.
- "Illinois was the furthest point west on the National Road" is the most accurate statement, as it did indeed terminate in Vandalia, Illinois.
- "Canals made it easy to reach the Pacific Ocean" is unrelated to the National Road.
Therefore, the best answer is that "Illinois was the furthest point west on the National Road."