When must you stop for a school bus?

Answer: C — When the bus has its stop arm extended

You must stop for a school bus when it has its stop arm extended. This signal indicates that children are getting on or off the bus, and it is crucial for ensuring their safety. The stop arm, along with the flashing red lights, serves as a warning to all drivers that they need to stop their vehicles and remain stopped until the lights stop flashing and the stop arm is retracted. This law is in place to protect children who may cross the street in front of or behind the bus and cannot be easily seen by drivers. It's important to note that merely seeing a bus on the road does not require a stop; the specific requirement is linked to the stop arm and flashing lights, which alert drivers to the necessity of stopping for safety reasons. Additionally, stopping only in residential areas or just when the lights are flashing does not cover the full legal requirement, which is centered around the presence of the stop arm.