building hydroelectric plants runoff from fertilized farm fields burning of fossil fuels release of chlorofluorocarbons from aerosol cans
I gave my students this multiple choice question: Which of these human activities most likely helped in depleting the ozone layer?

Only one answer is correct among these 4 choices:
- building hydroelectric plants
- runoff from fertilized farm fields
- burning of fossil fuels
- release of chlorofluorocarbons from aerosol cans

Could you tell me which one is correct?

release of chlorofluorocarbons from aerosol cans