Which battalion is not part of the Ranger Force?

The 5th Ranger Battalion is indeed not part of the modern Ranger Force as recognized today. The current Ranger Regiment consists of the 1st, 2nd, and 3rd Ranger Battalions, as well as the Special Troops Battalion and the Regimental Headquarters.

Historically, the 5th Ranger Battalion was a unit that existed during World War II but was disbanded after the war. The Ranger Force has been restructured and renamed over the years, and as of now, the officially recognized battalions are the 1st, 2nd, and 3rd. Therefore, the absence of the 5th Ranger Battalion in the contemporary structure is what makes this answer correct. Understanding the historical context of the Ranger units can help clarify their evolution and current organization.