In Lurnee, it takes 10 resources to produce 1 ton of cocoa and 13.5 resources to produce 1 ton of rice. In South Tyberg, it takes 40 resources to produce 1 ton of cocoa and 20 resources to produce 1 ton of rice. Lurnee has a comparative advantage over South Tyberg in cocoa. This follows the theory of comparative advantage, and we can say that engaging in free trade benefits all countries that participate in it; however, this conclusion stems from which of these inaccurate assumptions?