Answer:
Mississippi-Missouri River System
Explanation:
The transportation on Mississippi–Missouri River System started around the early period 1800s with the use of Steam Boats. It spans across 5,969 km long.
Erie canal first use was in 1821
Pony Express was a mail service
Transcontinental Highway in America first became operational in 1954
Hence, in this case, the correct answer is Mississippi-Missouri River System
