Which regulatory action can prevent substandard soldiers from reenlisting?

The option that can prevent substandard soldiers from reenlisting is the Bar to Reenlistment. This regulatory action specifically addresses the issue of a soldier’s performance and conduct, allowing the chain of command to formally indicate that a soldier is not eligible to reenlist due to performance issues, lack of motivation, or failure to meet required standards. The Bar to Reenlistment is a documented process that, once approved, places a soldier in a status that prohibits them from reenlisting until the reasons for the bar are resolved.

Other options, while they may play a role in a soldier's career and performance evaluations, do not have the specific effect of preventing reenlistment. A letter of reprimand serves as a formal discipline measure but does not automatically bar reenlistment. NCOER, or Non-Commissioned Officer Evaluation Report, is an evaluation tool used to assess a soldier's performance and potential, which may influence reenlistment but does not serve as a direct barring mechanism on its own. A field exercise is an operational training activity and has no bearing on a soldier’s reenlistment status. The Bar to Reenlistment is the definitive action to prevent those deemed substandard from continuing their service in the same capacity.