Final answer:
A placarded vehicle must carry a fire extinguisher capable of handling hazardous materials fires, such as those with a fluorinated solution, which is universally used now due to its effectiveness in extinguishing large-scale fires of organic liquids.
Step-by-step explanation:
A placarded vehicle, which refers to a vehicle that carries hazardous materials and is required to be placarded under transportation regulations, must carry a specific type of fire extinguisher. The fire extinguisher is necessary for addressing potential fires that might occur during the transport of dangerous goods. While dry-cleaning solvents and older fire extinguisher systems were once utilized, they are no longer recommended due to safety and environmental concerns. Instead, a fluorinated solution is able to spread across the burning surface and extinguish the fire effectively. This type of foam is used universally to fight large-scale fires of organic liquids and is recommended for vehicles carrying flammable goods.