Fire extinguishers must be rated and labeled by which entity?

Answer: A — County Fire Department

Fire extinguishers must be rated and labeled by the Underwriters Laboratories (UL), which is an independent safety science company that tests products for safety standards. UL certification indicates that a product has been thoroughly tested and meets established performance criteria. While various entities are involved in fire safety regulations and services, the UL label is recognized as a mark of safety compliance for fire extinguishers. The rating on the extinguisher provides crucial information about the types of fires it can extinguish, which is vital for ensuring appropriate usage in emergency situations. The other options involve organizations that might engage in fire safety education, prevention services, or regional fire codes, but they do not specifically have the authoritative role in rating and labeling fire extinguishers.