What provides official policies and procedures for all aspects of postal operations?

The correct answer is manuals, as they serve as comprehensive documents that articulate official policies and procedures governing postal operations. Manuals are typically structured in a way that provides clear, detailed instructions and standards for various processes, ensuring consistency and compliance across the organization. They are essential resources for employees, offering a reference point for best practices and protocols in postal services.

Guidelines, while useful, are often less formal and may not encompass the full range of policies and procedures that manuals do. They serve more as suggestions or frameworks rather than binding rules. Catalogs, on the other hand, generally focus on listing products or services available and do not provide the procedural detail necessary for operational practices. Therefore, manuals are distinctly suited for outlining the comprehensive policies and procedures essential for effective postal operations.