Which of the following chemicals replaced chlorofluorocarbons (CFCs) after their phase-out due to the Montreal Protocol?

Hydrofluorocarbons became the main substitutes for CFCs because they do not carry chlorine and so do not attack the ozone layer.

Perfluorocarbons are used in some industries but are extremely potent greenhouse gases, not the general CFC replacement.

Sulphur hexafluoride is a specialised insulating gas in electrical equipment and the most powerful known greenhouse gas, not a CFC substitute.

Halons contain bromine and were themselves banned for damaging ozone, so they could not replace CFCs.

HFCs proved effective as refrigerants, propellants and foaming agents in place of CFCs.

Because they still cause strong warming, the Kigali Amendment now schedules their phase down.