building hydroelectric plants runoff from fertilized farm fields burning of fossil fuels release of chlorofluorocarbons from aerosol cans
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Which of these human activities most likely helped in depleting the ozone layer?
Possibilities:
- building hydroelectric plants
- runoff from fertilized farm fields
- burning of fossil fuels
- release of chlorofluorocarbons from aerosol cans

release of chlorofluorocarbons from aerosol cans