You must not pass another vehicle if you see:

The correct answer encompasses all of the mentioned scenarios where passing another vehicle is prohibited due to safety concerns.

When you see a school bus with red flashing lights and an extended stop arm, it indicates that children may be entering or exiting the bus, which creates a dangerous situation. It is essential to stop and not attempt to pass the bus to ensure the safety of the children.

Approaching a hill or a curve where visibility is restricted presents another significant hazard. It’s impossible to see if there are oncoming vehicles or obstacles, increasing the risk of a collision if you attempt to pass.

Additionally, a solid yellow line in your lane signifies that passing is not allowed in that area. This marking is crucial for maintaining safe traffic flow and preventing accidents in zones where visibility or conditions may be unsafe.

Overall, all these circumstances highlight the importance of prioritizing safety on the road, making it clear why passing another vehicle should not occur in these situations.