At an intersection where a police officer is directing traffic, which signal must drivers obey?

Answer: C — Police officer

When a police officer is directing traffic at an intersection, drivers must obey the officer's signals. This takes precedence over other traffic control devices like traffic lights, road signs, and yield signs because the officer is there to manage the flow of traffic based on the current conditions, which may not be reflected in the static signals. The officer’s directions are aimed at ensuring safety and efficient movement of vehicles and pedestrians, often in response to situations that require immediate attention, such as accidents or construction. Therefore, regardless of any conflicting signals from traffic lights or signs, the directives from the police officer should always be followed to maintain orderly traffic and ensure public safety.