Which of the following branches is NOT part of the United States military?

The National Police Force is not part of the United States military, which is why it is the correct choice. The United States military comprises several branches, specifically the Army, Navy, Air Force, Marine Corps, and Coast Guard, all of which are organized under the Department of Defense or the Department of Homeland Security (in the case of the Coast Guard during peacetime). These military branches perform various defense-related functions, protect national security, and engage in military operations as needed.

In contrast, a National Police Force typically refers to a civilian law enforcement entity responsible for maintaining public order and enforcing laws within a country. It is not organized or operated under military command and lacks the combat capabilities and military structure of the branches mentioned in the other options.