Which of the following describes the trade benefits of a customs union?

The correct answer highlights the key characteristic of a customs union, which is the implementation of uniform tariffs on goods imported from non-member countries. This means that all member countries of the customs union agree to charge the same tariff rates on imports, creating a common external trade policy. This uniformity fosters trade by eliminating potential trade barriers among members and simplifying customs procedures when goods move within the union.

By applying the same tariffs, member countries can effectively protect their markets from external competition while promoting intra-union trade, as businesses can trade without additional costs related to varying tariffs among them. This setup encourages economic integration and can lead to greater efficiency and trade volume among member nations.

The other options do not encapsulate the primary benefit of a customs union effectively. While limited trade regulations can exist among member countries, that aspect is not as defining as the common external tariff feature. The free movement of labor may occur, but it is not a prerequisite characteristic of customs unions – it is more a feature of economic unions. Lastly, a common monetary policy would pertain to a monetary union, which is different from a customs union, as customs unions focus on tariffs and trade regulations.