Which of the following is a primary responsibility of a unit's first sergeant?

The primary responsibility of a unit's first sergeant centers around addressing personnel issues. This role is critical within military units, as the first sergeant serves as a direct link between the troops and the leadership, providing support and guidance on various personnel matters. This includes counseling service members on personal and professional issues, managing disciplinary actions, and ensuring the well-being and morale of the unit.

While developing training programs, managing budgets, and writing performance reports are important tasks, they are typically the responsibilities of other leadership positions within the unit. For example, training programs are often developed by the training NCO or unit commander, budget management falls under the purview of the unit's administrative or logistic functions, and performance reports are usually drafted by direct supervisors or officers rather than the first sergeant themselves. Thus, the first sergeant's focus on personnel issues is what makes this responsibility primary and essential in maintaining the overall effectiveness and readiness of the unit.