Why did Tubman have to take the runaways all the way to Canada instead of to a place in the North?

A Cities and towns in Canada had agreed to provide jobs for all of the runaways that Tubman brought.
B The cooler weather in Canada was helpful for runaways who became sick during the long journey.
C The Fugitive Slave Law required that runaways be returned to the South if found in the North.
D People in the North were no longer willing to provide food, shelter, or jobs for the runaways.