Explanation: To perform or supervise at-sea adjustments, servicing, or maintenance that could impact the proper operation of a GMDSS station, an individual must possess the specific technical qualifications outlined by the FCC. The **GMDSS Maintainer’s license** is precisely designed for this purpose, certifying the holder has the expertise to troubleshoot, repair, and ensure the correct functioning of GMDSS equipment in accordance with regulations. The **GMDSS Operator’s/Maintainer’s license** includes these same maintenance privileges. Other licenses are insufficient: * A **GMDSS Radio Operator’s license** authorizes *operation* of the equipment, not in-depth maintenance affecting its fundamental operation. * A **Marine Radio Operator’s Permit (MROP)** is for basic operation and does not qualify one for GMDSS maintenance. * A **General Radiotelephone Operator’s License (GROL)** with a Shipboard RADAR endorsement primarily covers radar maintenance and general radiotelephone operation, not the specialized maintenance of GMDSS systems which can impact their proper operation.