Which of the following provides specific directives for postal services?

The correct choice provides specific directives for postal services by detailing the expectations and requirements for job performance. This documentation typically outlines the standards and procedures that employees must follow in their everyday tasks, ensuring consistency and efficiency in service delivery.

Providing job performance directives helps to maintain a high level of service quality and compliance with regulatory standards. In a postal service context, these directives can cover a range of activities—from how to handle mail efficiently to customer interaction protocols.

While the other options include important materials—such as procedural handbooks that outline processes, service guidelines for broader service policies, and internal communication manuals for organizational messaging—they do not focus specifically on the job performance aspect that is key to an employee's daily responsibilities in a postal service role. Thus, directives aimed directly at job performance are essential for guiding employees effectively within the context of postal operations.