The correct answer is: "market integration and free trade".
If trade barriers between countries are reduced, such as tariffs or embargoes, national producers from every country will operate in larger markets as they will be able to reach national consumers but also foreign ones. This process is known as market integration.
Under a free trade regime, companies that participate in these international markets will be able to increase their production figures and to benefit from reaching economies of scale. This situation, together the increase in the number of competitors, leads to a larger variety and total amount of goods being commercialized at a cheaper price.
