Final answer:
The European Union (EU) has its own currency, the euro, which replaced several national currencies of its member states, though a few members retain their own currencies.
Step-by-step explanation:
The entity among the options provided that has its own currency is the European Union (EU). After World War II, European leaders sought to prevent future conflicts by tying their economies together, progressing from a free trade association to a common market, and eventually forming an economic union with the establishment of the EU.
A significant milestone for the EU was the introduction of a common currency, the euro, in the early 2000s. This currency replaced many national currencies, like the German mark and the French franc, although some member states have chosen to keep their own currencies. The EU also aims to facilitate the free movement of goods, labor, and capital across Europe.
It's important to note that while other regional trading agreements exist, such as NAFTA and ASEAN, they do not have their own currency. Also, while the European Union has established the euro, not all its members have adopted it; for example, Britain had retained the pound sterling until it ultimately left the EU in 2020.