What form should be filled out to request a replacement for a lost or damaged classified MRC?

The appropriate form to request a replacement for a lost or damaged classified MRC is the OPNAV 4790/7B (Category A). This form is specifically designed for reporting deficiencies and requesting replacements for Maintenance Requirement Cards (MRCs) that are categorized as classified.

By using the OPNAV 4790/7B (Category A), you ensure that the request is processed correctly within the framework established for handling classified materials. This form facilitates tracking and accountability measures that are critical when dealing with classified information, thereby enhancing security and compliance with regulations.

The other options listed pertain to different types of requests or issues. OPNAV 4790/2K and OPNAV 4790/CK have their specific purposes and do not apply to the context of replacing classified MRCs, while OPNAV 4790/7B (Category B) deals with a different classification of MRCs or maintenance concerns that are not classified. Hence, the choice of the OPNAV 4790/7B (Category A) is crucial for the task at hand.