Which of these is usually a result of free trade between countries?

Free trade results in greater international economic integration. The abolishment of tariffs, quotas and other protectionist measures result in lower prices and more choices for consumers, greater world efficiency and efficiency of exporting producers as competition increases.

The theory of comparative advantage states that countries with favorable factor endowments for a specific product will be able to produce that at a lower opportunity cost than a potential trading partner. This allows for greater world efficiency because as few resources as possible are used for the production of goods and services.

your answer would be (b)