Given the Effect of Group Size on Collective Action Problems,what

Given the effect of group size on collective action problems,what scenario is likely to be the most successful?

A) Over 180 countries sign an agreement to reduce pollution in oceans.
B) Twenty Mediterranean countries agree to reduce pollution in the Mediterranean Sea.
C) Germany,Austria,Slovakia,Hungary,Croatia,Serbia,Romania,and Ukraine sign an agreement to reduce pollution in the Danube River.
D) Uganda,Kenya,and Tanzania sign an agreement to reduce pollution in Lake Victoria.
E) The United States and Mexico sign an agreement to reduce pollution along their shared border.