Which Is True of Collective Security Organizations

Which is true of collective security organizations?

A) They must exclude those countries that might initiate hostilities.
B) They have functioned effectively in deterring aggression by major powers.
C) They work best when they allow small states to participate fully in all decisions.
D) They tend to fail if states are unwilling to use force against aggressors.
E) They can only exist between states that speak the same language.