Which of the following is NOT considered a method to overcome trade barriers?

The answer identifies tariffs as the option that is not a method to overcome trade barriers. This is accurate because tariffs are actually a form of trade barrier rather than a means of overcoming them. A tariff is a tax imposed on imported goods, which raises their price and makes them less competitive compared to domestic products. This can discourage imports and protect local industries, but it does not facilitate or promote free trade.

In contrast, free trade agreements, trade blocs, and customs unions are all strategies designed to reduce or eliminate trade barriers among member countries. Free trade agreements eliminate tariffs between participating countries, while trade blocs generally create a larger market by integrating several economies, and customs unions establish a common external tariff and allow free trade among member nations. Thus, while tariffs are a protectionist tool, the other options are intended to encourage trade by mitigating or eliminating barriers.