Explanation: FCC-licensed ship stations operating in international waters are governed by a dual regulatory framework. Domestically, they must comply with Part 80 of the FCC Rules, which specifically covers the maritime services. These rules dictate licensing requirements, operational procedures, and technical standards for U.S.-flagged vessels, reflecting U.S. law and its obligations under international treaties. Globally, such stations must also adhere to the international Radio Regulations formulated by the International Telecommunication Union (ITU), a specialized agency of the United Nations. These regulations ensure global interoperability, prevent interference, and standardize communication procedures in international waters. Additionally, the U.S. is party to various international agreements, such as the Safety of Life at Sea (SOLAS) convention, which further define maritime communications requirements. Options A and D are incorrect because the IMO focuses on general maritime safety standards (not direct radio regulations), a union has no regulatory authority, and FCC departmental details don't define the regulations themselves. Option C is partially correct in identifying the ITU but omits the crucial national FCC regulations and uses an imprecise term for the ITU's governing document (the Radio Regulations).