Just War Theories Are Attempts to Explain

Just war theories are attempts to explain

A) how war is actually acceptable because "it's just war."
B) how war can never really be logically justified because all rationale for going to war is "just a theory."
C) how war is never morally acceptable, given that only God can rule over all humanity.
D) what the conditions and situations would have to be for a war to be justified.