Which vehicles use blue flashing lights?

Answer: B — Emergency service vehicles

Blue flashing lights are typically used by emergency service vehicles such as police cars, fire trucks, and ambulances to quickly alert other drivers and pedestrians of their presence and the urgency of their situation. While commercial trucks and taxi cabs may have lights on their vehicles for safety purposes, they do not typically use blue flashing lights. School buses also use flashing lights, but they are typically amber in color for cautionary purposes, not blue for emergency situations. Therefore, the most accurate answer is B Emergency service vehicles.