Which rank corresponds to the O-5 designation?

The rank that corresponds to the O-5 designation is Lieutenant Colonel. In the military ranking system, officers are classified with a number that indicates their pay grade, referred to as the "O" scale. The number 5 in O-5 specifically identifies the rank of Lieutenant Colonel within most branches of the U.S. military, such as the Army, Air Force, and Marine Corps.

Lieutenant Colonel is a senior field officer rank and is positioned above Major (O-4) and below Colonel (O-6). This rank carries significant responsibilities, often involving the command of battalion-sized units or staff positions at various organizational levels within a military structure.

The other ranks listed do not align with the O-5 designation. Captain (O-3) is a junior officer rank, Brigadier General (O-7) is a one-star general which is above O-5, and Rear Admiral (Lower Half) (O-7) is a Navy rank that also exceeds O-5. Therefore, the only correct designation for O-5 is Lieutenant Colonel.