Final answer:
Hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) are the most promising replacements for Halon extinguishers.
Step-by-step explanation:
The most promising replacement for Halon extinguishers are hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs). HFC-134a and HCFC-141b are examples of these compounds. They are commonly used as fire extinguishing agents due to their low toxicity and environmental impact.