What are chlorofluorocarbons (CFCs) primarily used for?

Chlorofluorocarbons (CFCs) are primarily used in the production of plastics and foams, particularly those found in insulation materials and packaging. Their chemical properties make them effective as solvents and propellants in aerosol products, which is essential during the manufacturing processes of various plastic items and foam products. CFCs were once widely used in refrigeration and air conditioning systems as well, helping to maintain the necessary temperature in these applications.

The other options do not accurately reflect the primary uses of CFCs. Fertilizers are typically derived from organic or inorganic compounds that are distinct from CFCs. Similarly, CFCs are not utilized as a fuel source, nor are they employed in water purification processes. These uses do not align with the characteristics and applications of CFCs in industrial contexts.