Explanation: Statement D is false because all communications involving Safety of Life at Sea (distress, urgency, and safety communications) must always be logged by a compulsory vessel, regardless of its location or any other operating condition. GMDSS regulations require a detailed record of these critical communications to be maintained in the vessel's radio log. The incomplete phrase "as long as the compulsory vessel was not" implies a condition under which logging would *not* be required, which contradicts the mandatory nature of logging all safety-related communications. Statements A and B are identical and correct. Compulsory vessels (those required by SOLAS to participate in GMDSS) must indeed carry at least two licensed GMDSS Radio Operators while at sea to ensure continuous watchkeeping and operational redundancy. Statement C, while incomplete ("by the GMDSS"), is likely referring to GMDSS personnel. A licensed GMDSS Radio Operator (e.g., General Operator's Certificate holder) is responsible for the operational performance of the GMDSS equipment, including basic fault-finding and ensuring its proper function. A GMDSS Maintainer specifically holds a license for more in-depth adjustments and repairs. Therefore, within the scope of GMDSS qualified personnel, adjustments and maintenance can be performed, making the general intent of the statement true.