Which group of refrigerants is specifically restricted for sale?

The group of refrigerants that is specifically restricted for sale is comprised of HCFCs and CFCs. Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are both ozone-depleting substances that have been the focus of various environmental regulations, such as the Montreal Protocol. These regulations aim to phase out the production and use of substances that deplete the ozone layer due to their harmful environmental impact.

CFCs have been banned in many applications due to their significant contribution to ozone depletion, while HCFCs, though considered a transitional refrigerant, are also being phased out due to their ozone-depleting potential, albeit to a lesser extent compared to CFCs. Therefore, the correct identification of HCFCs and CFCs as a restricted group aligns with regulatory measures aimed at protecting the environment and mitigating the effects of climate change.

The other options include refrigerants that do not share the same level of restriction or concern regarding ozone depletion, making them less relevant to this particular question.