What did lincoln most likely mean by the phrase "all persons held as slaves are, and henceforward shall be free"?
a. it is intended to increase the numbers of freed slaves who enlist in the union army.
b. it is a promise to the slaves that actual freedom will come throughout the south, but only when the war is over.
c. it is a threat directed against southern slave-owners who will lose their property.
d. it is a warning to his generals that they must work harder to win the war.