Which rank is denoted by just one disc?

The rank that is indicated by just one disc is Cadet 2nd Lieutenant. In JROTC ranks, the insignia for Cadet 2nd Lieutenant typically consists of a single disc, which clearly distinguishes this position from higher ranks that incorporate additional insignia or symbols.

In contrast, Cadet Lieutenant, Cadet Captain, and Cadet Staff Sergeant each have more complex insignia, such as additional discs or chevrons. This system of insignia helps to visually communicate levels of hierarchy and responsibility within the organization, which is essential for maintaining order and structure in military programs.