Concept:Chlorine gas is a key raw material in making certain industrial organic compounds.
Explanation:Chlorine gas reacts with hydrocarbons to form chlorofluorocarbons (CFCs).
CFCs were widely used as refrigerants, aerosol propellants, and foam-blowing agents.
However, CFCs damage the ozone layer, so their production is now restricted.
Methane, ammonia, and ethanol are not primarily produced using chlorine gas.
Therefore, the correct industrial compound is chlorofluorocarbons.
Answer:A. Chlorofluorocarbons (CFCs)