Consider the following : 1. Carbon monoxide 2. Methane 3. Ozone 4. Sulphur dioxide Which of the above are released into atmosphere due to the burning of crop/biomass residue?

Biomass burning releases Carbon monoxide and Methane through incomplete combustion, and Sulphur dioxide from the sulphur naturally present in plant tissues; it also emits precursors like nitrogen oxides and volatile organic compounds that react in the atmosphere to form ground-level Ozone. Option (d) is correct because all four substances are either directly emitted or chemically produced as a result of the combustion process, making more restrictive options like (a) or (c) incomplete. The core concept tested is the diverse range of primary and secondary atmospheric pollutants generated by agricultural residue burning.