- Photochemical smog formation requires sunlight, NOx, and VOCs. - Key components of photochemical smog include Ozone (O₃), Peroxyacyl Nitrates (PANs), aldehydes, ketones, hydrogen peroxide (H₂O₂), and nitric acid (HNO₃). - Option A lists some of these components (H₂O₂, organic peroxide) and a key precursor (NO) and a necessary reactant (O₂).