Explanation: A DSC Safety priority call (equivalent to the radiotelephone "SECURITE" call) is used for messages concerning the safety of navigation or important meteorological warnings. It indicates that the station has an important message to transmit concerning maritime safety, but it does not represent an immediate grave and imminent danger to a vessel or person. In scenario C, "A lifeboat has been lost over the side in heavy weather and is adrift," the lost lifeboat poses a hazard to navigation for other vessels and represents a significant safety concern for the vessel itself (reduced lifesaving capability). While serious, it does not typically present an *immediate grave and imminent danger* to the vessel or persons on board, making it appropriate for a Safety call. Conversely: * **A) A crew member is missing and presumed lost overboard** and **B) There is a fire in the engine room** both represent *grave and imminent danger* to life or the vessel. These situations would require a **Distress** priority call (MAYDAY). * **D) A medical situation that did not present an imminent danger of loss of life** would typically warrant an **Urgency** priority call (PAN PAN). This indicates a very urgent message concerning the safety of a vessel or a person on board, but without the immediate grave danger of a Distress situation.