What is the primary function of an ensign?

The primary function of an ensign is to indicate nationality among military or naval vessels. An ensign is a flag that represents a particular nation, and it is prominently displayed on ships to signify the country to which the vessel belongs. This is crucial for identification on the high seas, as vessels from different nations must respect each other's sovereignty and regulations.

By flying the national ensign, a ship signals its allegiance and ensures that it is recognized and respected by other ships and nations. This visibility also plays an essential role in naval protocol and operations, as it helps avoid conflicts and ensures compliance with international maritime law.

The other options do not accurately represent the role of an ensign in naval context. While currency and decorative flags may have their own significance, they do not pertain to the core function of an ensign in identifying a ship's nationality. Additionally, surrender is communicated through other internationally recognized flags, such as the "flag of truce" or the "flag of surrender."