The answer is(B) increased trade between Northwest and Midwest,further isolating the south economically.
Till the Erie Canal was not opened, New Orleans was the only port city with an all water route to the interior of the United States.The New Englanders and the Europeans were opposed to slavery but Northerners became more hardened and it set up confrontation.
It also transformed the Midwest into America's bread basket by the new settlers and reduced the dependence of the industrial North on the agriculturally dominant South.
