Identify the correct option from the following about the proportion of different gases in Biogas?

Biogas is a renewable fuel produced through the anaerobic digestion of organic matter. Its primary component is methane (CH4), which typically accounts for 50–75% of the total volume [1]. The second most abundant gas is carbon dioxide (CO2), comprising approximately 25–50% [1]. Other gases are present in much smaller or trace amounts, including nitrogen (N2), which usually constitutes less than 5–10% of the mixture [1]. Hydrogen sulfide, hydrogen, and oxygen may also be present in very low concentrations, often below 1-3%. Therefore, the correct relative proportion of the major gases in biogas is Methane > Carbon dioxide > Nitrogen. While atmospheric air is dominated by nitrogen, biogas is specifically enriched with methane and carbon dioxide due to the biological decomposition process.

Sources

1. [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 20: Earths Atmosphere > Permanent Gases of The Atmosphere > p. 271