Which of the following processes would explain ozone losses in the atmosphere ? When ozone is exposed to 1. CFCs and UV radiation. 2. long winter circumpolar winds to form ice crystals. 3. singlet oxygen atom and chlorine monoxide. Select the correct answer using the code given below :

1. A1, 2 and 3
2. B2 and 3 only
3. C1 and 2 only
4. D1 and 3 only