What are the requirements to be met by fire extinguishers to be carried on buses?

You answered correctly. Fire extinguishers that must be carried on buses in Germany require authorization for fire classes A, B, and C. This means they must be suitable for extinguishing solid, liquid, and gas fires. Additionally, regulations specify that the extinguisher must contain at least 6 kg of filling material. This is to ensure the device can handle larger fires that may occur in a bus. A 4 kg extinguisher does not meet the necessary capacity for buses.

Remember, both the correct fire classification and the minimum amount of extinguishing material are required for compliance. This ensures passenger safety in case of fire emergencies on buses.