who decides which currency each country in the world uses?\nthe united nations\neach individual country\nthe…

Brief Explanations:

Each country has its own sovereignty and economic system. The choice of currency is a domestic economic decision. The United Nations is an international organization for peace and cooperation, not for determining each country's currency. The European Union is a regional organization, and its influence is mainly within the EU. The United States cannot decide the currency of all countries in the world.

Answer:

each individual country