When a company officer arrives first on a fire scene, the officer is in command until:

• A. the chief of the department arrives.
• B. Arrival of the senior shift officer.
• C. The fire is declared under control.
• D. a higher-ranking officer arrives and assumes command.

Answer: (D)

The key idea is transfer of command on an evolving incident. The first company officer on the scene establishes incident command and remains in control until a higher-ranking officer arrives to assume command. Once that higher-ranking officer arrives, they take over the incident command, and the initial officer relinquishes command. This transfer is about authority and supervision on scene, not about the fire being under control or specific individuals arriving. In practice, any higher-ranking officer—whether a battalion chief, incident commander, or other senior officer—may assume command, depending on who arrives first.

So, command passes to the higher-ranking officer who arrives and assumes command.