To Fully Reap the Benefits of Production According to Comparative

To fully reap the benefits of production according to comparative advantage, it is necessary that:

A) an environment of free trade exist between nations.
B) trade restrictions be imposed to protect the outputs of each nation's economy.
C) some nations be willing to suffer significant decreases in their standards of living.
D) nations enter into detailed agreements as to the economic systems under which they will operate.