What Caused the Largest Geographic Movement of Slaves from Plantations

What caused the largest geographic movement of slaves from plantations in the South before the Civil War?

A) Slaves voluntarily deserted their owners to flee to British lines during the Revolutionary War.
B) The Americans forced slaves to relocate to Britain as part of the treaty after the Revolutionary War.
C) Slaves escaped to northern states, which had all passed emancipation laws.
D) A prolonged drought in the South caused most planters and slaves to move to the North.
E) Slaves moved West to work in the mines since there was no longer much demand for tobacco.