By international agreement, which ships must carry radio equipment for the safety of life at sea?

The correct answer states that cargo ships of more than 300 gross tons and vessels carrying more than 12 passengers are required to carry radio equipment for the safety of life at sea, according to international agreements like the Safety of Life at Sea (SOLAS) convention. This regulation ensures that these vessels are equipped for effective communication in emergencies, thus protecting the lives of passengers and crew during maritime operations.

Cargo ships exceeding the specified gross tonnage and vessels transporting a significant number of passengers are more likely to encounter situations necessitating immediate assistance or coordination with rescue operations. By mandating radio equipment on these ships, international maritime safety standards aim to enhance navigation safety and improve response times in distress scenarios.

Other options suggest various thresholds for communication equipment that do not align with the specific stipulations set by international agreements governing maritime safety. The correct choice highlights the importance of radio equipment as a critical tool for communication and coordination in ensuring safety at sea.