Which of the following statements about the depletion of ozone layer is correct?

• A. The problem of ozone depletion is less serious at poles because \[N{{O}_{2}}\] solidifies and is not available for consuming \[CI{{O}^{\bullet }}\] radicals.
• B. The problem of ozone depletion is more serious at poles because ice crystals in the clouds over poles act as catalyst for photochemical reactions involving the decomposition of ozone of \[C{{l}^{\bullet }}\] and \[CI{{O}^{\bullet }}\] radicals.
• C. Freons, chlorofluorocarbons, are inert. Chemically, they do not react with ozone in stratosphere.
• D. Oxides of nitrogen also do not react with ozone in stratosphere.