Explanation: Compulsory vessels operating under the Global Maritime Distress and Safety System (GMDSS) are required by FCC regulations (47 CFR Part 80, Subpart W, specifically 80.59) to have their GMDSS radio station inspected annually. This inspection must be conducted by the Federal Communications Commission (FCC) or a designated, FCC-recognized authority, such as an independent inspector. Option A is incorrect because while the U.S. Coast Guard enforces maritime safety, the specific *radio station inspection* for GMDSS compliance falls under the FCC's purview. Option C is incorrect; there is no general requirement for an external GMDSS inspection every six months based on sea areas. Option D is incorrect as the annual external inspection cannot be waived by performing internal monthly checks; these internal checks are a necessary ongoing maintenance practice, but they do not replace the formal annual inspection.