Which of the following gun salutes is NOT authorized?

The 10-gun salute is not authorized within the framework of military honors and customs. In the U.S. Navy and other branches of the armed forces, specific established practices dictate which gun salutes are appropriate for various occasions. The 21-gun salute is reserved for national holidays and is the highest honor. The 13-gun salute historically commemorates the original 13 colonies and is used in various ceremonial contexts, such as for former presidents. The 7-gun salute is typically used for the death of a President or other significant honors. Each of these salutes has an established purpose and background, while the 10-gun salute does not align with any recognized standards or customs in military traditions.