Air pollutants that produce photochemical oxidants include:

Photochemical oxidants are the secondary pollutants that are formed when the primary pollutants like hydrocarbons, oxides of sulphur, oxides of nitrogen react with sunlight. The nitrous oxide, nitric oxide and nitric acid are contributed by the vehicular exhausts, burning of fossils, fertilizers etc. The major products of this reaction include tropospheric ozone, peroxyacetyl nitrate and aldehydes. They also contribute to the formation of the photochemical smog. Hence, the correct answer is 'Nitrous oxide, nitric oxide and nitric acid'.