It Was Difficult for Runaways to Leave the Deep South

It was difficult for runaways to leave the Deep South because southerners:

A) placed guards around the periphery of slave quarters.
B) used hunting dogs to track escaped slaves.
C) used sources in the Underground Railroad to catch escaped slaves.
D) employed slavedrivers along state borders to catch runaways.
E) used the Underground Railroad to organize slave patrols.