Which of the Following Is True of Chlorofluorocarbons

Which of the following is true of chlorofluorocarbons?

A) they can easily be eliminated as they are used for so few manufacturing processes as to be unimportant.
B) they are used in refrigeration systems,as propellants in spray cans,and to make foam products.
C) they are used for storing chemicals in large manufacturing facilities.
D) they are unregulated in developing countries,so do not need to be regulated in North America.
E) they contribute to small changes in carbon dioxide levels.