Why, According to McMahan, Doesn't the Right to Self-Defense Justify

Why, according to McMahan, doesn't the right to self-defense justify the traditional principles of just war theory?

A) Because the right to self-defense applies to individuals, whereas the principles of just war apply to countries.
B) Because the right to self-defense does not apply to someone who is being attacked because he or she attacked someone else.
C) Because the right to self-defense is based on jus in bello, not vice versa.
D) Because the right to self-defense assumes a right to life that soldiers forfeit when they enter a war zone.