What entity must approve the structure of the MOSC?

The correct answer is that the structure of the Military Occupational Specialty Codes (MOSC) must be approved by the Human Resources Command (HRC). HRC is responsible for the overall management of military personnel and manages the Army's human resources policies, including the development and approval of the structure associated with military occupational specialties. This process ensures that the MOSC align with the Army's needs and mission objectives, and the HRC plays a critical role in maintaining the standards for various military roles.

In the context of military operations and personnel management, HRC serves as the central authority. This command oversees the classification, assignment, and allocation of personnel based on the approved structures of the MOSC. The authority of HRC in these matters underscores the importance of having a standardized and officially sanctioned set of codes, which helps ensure that personnel are effectively matched to the correct occupations based on their training and skills.

The other entities mentioned, like the Unit Commander, Department of Defense, and Army Chief of Staff, do not have the direct authority or responsibility for the approval of the MOSC structure in the same way that HRC does. While they may influence or take part in discussions about personnel management, the specific approval of MOSC structure resides with the Human Resources Command.