What effect did canals have on people living in the eastern united states?

Two hundreds years ago, New York legislators authorized a commission to survey the exact route of the Erie Canal that would link the Hudson River in Albany and Lake Erie in Buffalo. When it opened in 1825, the 360-mile ribbon of water not only proved to be an engineering marvel, it changed the course of American history in eight ways. Prior to the construction of the Erie Canal, most of the United States population remained pinned between the Atlantic Ocean to the east and the Appalachian Mountains to the west. By providing a direct water route to the Midwest, the canal triggered large-scale emigration to the sparsely populated frontiers of western New York, Ohio, Indiana, Michigan and Illinois.
Before the opening of the Erie Canal, New Orleans had been the only port city with an all-water route to the interior of the United States, and the few settlers in the Midwest had arrived mostly from the South.

Ithink the answer should be a.