This mechanism shows the conversion of ozone to oxygen in the upper atmosphere. What is the overall reaction from the mechanism? Step 1: Cl + O3 → ClO + O2 Step 2: O + ClO → Cl + O2 A. O3 + Cl → O2 + ClO B. O3 + ClO → 2O2 + Cl C. 2O3 → 3O2 D. 3O2 → 2O2