When a unit is at the location, which code is used?

The correct choice indicates that the code "AL" is used when a unit is at the location. In dispatch and communications, specific codes are designated to effectively convey the status of units in the field. The "AL" code typically stands for "At Location," indicating that the unit has arrived at the specified site and is ready to take action or provide assistance as required. This messaging is crucial for operational clarity and coordination, ensuring that all relevant personnel are aware of the unit’s status in real-time.

The other options represent different statuses or commands that do not specifically denote the unit's presence at a location. For instance, they could indicate other operational states, such as being en route, unavailable, or engaged in another task. Therefore, using "AL" accurately communicates the situation and helps maintain effective dispatch management practices.