Final answer:
The guidelines for deferring advancement or frocking of enlisted members who fail their PFA are found in OPNAVINST.
Step-by-step explanation:
The instructions to defer advancement or frocking of enlisted members who have failed their most recent Physical Fitness Assessment (PFA) are outlined in OPNAVINST which stands for Chief of Naval Operations Instructions.
The other options, such as NAVADMIN, BUPERSINST, and SECNAVINST, refer to other types of naval publications, but the guidelines for physical readiness program and related administrative actions would most commonly be found in the OPNAV instructions.