Which military branch's retail system was first to introduce the modern self-service supermarket format to the U.S. armed forces in 1941, revolutionizing on-base shopping?

The Post Exchange (PX) system has been a cornerstone of military life for generations, providing essential goods and boosting morale for service members worldwide. These unique retail establishments have evolved from simple sutler wagons following troops to sophisticated modern shopping centers. Beyond commerce, they represent a fascinating intersection of military history and retail innovation, creating a distinct shopping culture that has influenced civilian retail while serving those who serve.

This is a live public trivia poll on AIPolls.Net. Vote and see real-time results.

U.S. Army Exchange Service
Navy Exchange (NEX)
Marine Corps Exchange
Air Force Exchange Service (it wasn't yet independent from the Army)