What type of message is used to tell firefighters on the interior command is switching to a defensive strategy and they must exit the building immediately?

The correct answer is the emergency message, which is specifically designed to convey critical information that requires immediate attention and action. In the context of firefighting, when interior command switches to a defensive strategy, it indicates a significant change in the situation that poses a greater risk to the firefighters inside. An emergency message is used in such scenarios to ensure that all personnel understand the urgency of the situation and the necessity to evacuate the structure without delay.

This type of message is characterized by its direct and clear nature, aimed at facilitating a rapid response to protect lives. Unlike routine messages, which are generally informational and do not require immediate action, or advisory messages that might provide guidance without the urgency, emergency messages demand immediate compliance and are crucial for the safety of all involved. General information messages, on the other hand, are less urgent and serve to provide background or contextual information rather than prompt immediate action.