Which of the following contributes to global warming?

The correct answer, which is all of the above, acknowledges that all the listed compounds—CFCs, HCFCs, and HFCs—contribute to global warming. CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons) are known for their role in ozone depletion, but they are also potent greenhouse gases that can trap heat in the atmosphere. HFCs (hydrofluorocarbons), while introduced as a less harmful alternative to CFCs and HCFCs, are still significant contributors to global warming due to their high global warming potential.

Each of these substances has varying lifetimes in the atmosphere and varying abilities to trap heat, thus playing a role in climate change. While HFCs were designed to replace CFCs and HCFCs in many applications, their presence in the atmosphere still poses a substantial threat to the environment, making it critical to manage and mitigate their emissions. Recognizing that all these compounds contribute to global warming is essential in efforts to combat climate change and implement effective regulations aimed at reducing their usage.