When you see a school bus with flashing red lights:

Answer: B — Stop in the opposite lane of traffic

When you see a school bus with flashing red lights, you should stop in the opposite lane of traffic. This is because school buses are required to stop and let children on and off the bus safely. Stopping in the opposite lane of traffic ensures that you are not passing the bus and potentially putting children in danger. Reducing your speed (option A) may not be sufficient enough in this situation and may still put children at risk. Stopping only if the red lights are flashing (option C) is incorrect because the lights are there to alert you to stop, not to indicate that it's optional. Finally, keep driving (option D) is incorrect because it is illegal to pass a school bus with flashing red lights, even if you are on the opposite side of the road. It is important to always follow traffic laws and prioritize the safety of children.