Multiple choice Which of the following are ozone depleting substances? Chlorofluorocarbons (CFCs) Hydrofluorocarbons (HFCs) Hydrochlorofluorocarbons (HCFCs) Both B and C Reveal answer Fill a bubble to check yourself D Correct answer Explanation Both Hydrofluorocarbons (HFCs) and Hydrochlorofluorocarbons (HCFCs) are substances that contribute to ozone depletion or global warming, and are regulated under international agreements.