Which of the following is an example of HFCs?

HFCs, or hydrofluorocarbons, are a class of compounds that have been widely used as refrigerants. R-134a is a well-known example of an HFC. It is widely utilized in automotive air conditioning systems and has effectively replaced older refrigerants that are more harmful to the ozone layer. HFCs like R-134a do not deplete the ozone but may contribute to greenhouse gas emissions, which is why their use is under scrutiny.

R-12 is a CFC (chlorofluorocarbon), R-22 is an HCFC (hydrochlorofluorocarbon), and R-404A is a mixture of HFCs but does not represent a single HFC itself. By recognizing the chemical classifications, it becomes clear that R-134a fits squarely within the category of HFCs, making it the correct choice for this question.