This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
The maximum ozone concentration in polluted atmosphere is dependent on the concentration and ratio of nitrogen oxides and which one of the following- 
Select and explain. 
A. Carbon monoxide, B. Lead, C. Volate organic compounds, D. Sulphur dioxide
C: Volate organic compounds
Answer: C: Volate organic compounds 
Explanation: Ans. is 'c' i.e., Valate organic compounds Ground level ozone is formed from Nitrogen Oxides (NO) and valati le organic compounds (VOC), e.g., Methane