What made canals a popular transportation alternative?

A) They were cheap to build.
B) They required little manpower
C) American engineers were well-educated in canal building.
D) They connected inland waterways to larger transportation systems.

Transportation Systems

Infrastructure and vehicles designed for the movement of goods and people from one location to another, including roads, railways, airways, waterways, and pipelines.

American Engineers

Professionals from the United States engaged in the application of scientific principles to design, construct, and maintain structures, machines, and systems.