Which publication is used in addition to command directives for preparing naval correspondence?

The correct choice serves as the primary guidance for the preparation of naval correspondence, supplementing command directives. SECNAV M-5216.5 is the Standard Navy Correspondence Manual, which provides specific instructions on preparing, formatting, and handling naval correspondence. This publication contains detailed procedures, examples, and standards that ensure consistency and professionalism in communication within the Navy and Marine Corps.

While SECNAVINST 5216.5 is related to similar topics, SECNAV M-5216.5 is specifically focused on the formatting and rules governing correspondence. U.S. Navy Regulations cover a wider range of operational guidelines and conduct, which, while important, do not specifically address correspondence preparation. NAVFAC P-80 deals with facilities engineering and related topics, making it irrelevant for the preparation of naval correspondence. Hence, SECNAV M-5216.5 is the go-to publication for such tasks.