What situation requires the use of an international urgency signal?

The situation that requires the use of an international urgency signal is specifically associated with emergencies where there is an immediate need for assistance or a critical situation that requires prompt attention. The international urgency signal, indicated by the distress call "Mayday" or similar alerts, serves to communicate urgency and the necessity for rapid response. This signal is distinct from routine communications or less urgent situations where standard communication methods would suffice. Additionally, security alerts may involve concerns, but they do not specifically necessitate the urgency signal unless lives or safety are at immediate risk. Understanding this context clarifies why the other options do not align with the requirements for utilizing an international urgency signal.