Which of the following statements is not true when approaching a school bus from the rear?

Answer: C — You must pass

When approaching a school bus from the rear, you must not pass the bus as it could potentially put the lives of children in danger. Option A is incorrect because it is the law to stop when approaching a school bus from either direction, unless there is a physical barrier between you and the bus. Option B is incorrect because turning on your headlights is not a requirement for approaching a school bus from the rear. Option D is incorrect because when a school bus is stopped and displaying its stop sign and flashing lights, you must not exceed 10 mph. This is a lower speed limit than 25 mph. Therefore, option C is the only incorrect statement as it goes against the safety guidelines when approaching a school bus from the rear.