What unit manpower document sequence is primarily used to apply manpower standards?

The correct answer is that the functional account code is primarily used to apply manpower standards. This code serves as an essential identifier that classifies different types of activities or functions within an organization, thereby allowing for the appropriate allocation of manpower according to established standards.

Functional account codes play a crucial role in linking personnel requirements to specific missions or functions and help ensure that the right number of personnel are assigned to each task or operation. They provide a systematic way to gather and analyze data about manpower needs, making them vital in planning and decision-making processes.

While other options like document sequence number, standard code, and authority code may have their own specific purposes in a broader context of manpower administration, they do not directly relate to the application of manpower standards in the same comprehensive manner that functional account codes do. The use of functional account codes facilitates efficiency and accountability in managing manpower resources.