Explanation: An MMSI (Maritime Mobile Service Identity) is a unique 9-digit number assigned to identify maritime stations. The first three digits of an MMSI are called the Maritime Identification Digits (MID), which specify the country of registration for the ship or station. For U.S. flag ship stations, the MIDs assigned are 303, 338, 366, 367, 368, and 369. * **C) 303236824:** This MMSI begins with **303**, which is one of the MIDs designated for the United States. Therefore, it indicates a U.S. flag ship station. * **A) 430326890:** This MMSI begins with 430, which is the MID for Japan. * **B) 033609991:** An MMSI for a ship station typically does not begin with 0. The first digit being 0 usually indicates a group call or a coast station, not a ship station. * **D) 257326819:** This MMSI begins with 257, which is the MID for Portugal.