Naval officers in pay grades ______________ are called junior officers.

The classification of naval officers as junior officers is accurately represented by those in the ranks of O-1 to O-3. This group typically includes Ensigns (O-1), Lieutenants Junior Grade (O-2), and Lieutenants (O-3). These ranks are associated with early career stages in an officer's journey, where they are still building experience and often holding subordinate leadership roles.

In contrast, officers in the O-4 to O-6 range are considered senior officers, as they have more experience and typically serve in leadership roles that require significant responsibility. The ranks of O-7 and above are classified as flag officers or senior leaders, who hold high command positions. Warrant officers, designated by the W-1 to W-3 ranks, are also distinct from the junior officer category, as they specialize in technical areas and hold different responsibilities within the naval structure. Therefore, the distinction of junior officers being specifically those in pay grades O-1 to O-3 is clear and aligns with military organizational norms.