During the Civil War in the United States, Joseph Lieber

During the Civil War in the United States, Joseph Lieber created the Lieber Code. What was the Lieber Code?

A) A secret code used in communications between soldiers fighting for the North
B) A document outlining how noncombatants were to be treated
C) An agreement between the U.S. and Great Britain in which the British agreed not to intervene in the war
D) The written outline of how slaves would be liberated after the war