Realists Argue That States' Concern with Relative Gains Will Undermine

Realists argue that states' concern with relative gains will undermine international cooperation.What do they mean by this?

A) States will not cooperate since they have relatively little to gain from doing so.
B) States cannot be sure they will gain anything from cooperation,so they have little incentive to try.
C) Because it is relatively costly to form international institutions,realists believe it is a waste of resources to contribute to cooperative endeavors.
D) States will be reluctant to cooperate even for mutual gain,because their partners may benefit more,gaining additional power to use against them in the future.