Despite the fact that the United Nations charter made it illegal for any state signing it to use force, except in cases of self-defense or collective security, the Security Council has rarely used its full power to take action against violators because

__________.

a. it closely resembled a classical balance of power mechanism attached to a collective security system, and ran into familiar problems of power politics, self-interest, and free rider issues
b. its decisions were not binding on any states, given the ambiguity of charter wording
c. problems of power politics, member self-interest, and free rider problems meant that major decisions have more often been left to ad-hoc tribunals instead
d. its permanent membership status did not change to reflect changes in relative power status among countries of the world.

Answer: A