When are you allowed to pass a school bus unloading children?

Answer: A — When you are driving in the opposite direction on a two way street

Passing a school bus when it is unloading children is generally prohibited in order to ensure their safety. Option A is the only correct answer, as it specifically addresses the situation where you are on a two-way street driving in the opposite direction. Option B is incorrect because the red lights flashing signal that children are getting on or off the bus, making it illegal to pass. Option C is incorrect because children could potentially be out of sight but still in the process of loading or unloading the bus. Option D is incorrect because the yellow lights are a warning for the driver to prepare to stop, not to pass the bus. Therefore, the only permissible time to pass a school bus unloading children is when you are on a two-way street driving in the opposite direction as the bus. However, it is always important to exercise caution and follow traffic laws when passing a school bus.