Biogas or gobar gas is produced by anaerobic breakdown or digestion of biomass.
Biogas or gobar gas is a methane-rich fuel gas produced by anaerobic breakdown or digestion of biomass with the help of methanogenic bacteria. It is made up of methane (50 - 70%), carbon dioxide (30 - 40%) with traces of nitrogen, hydrogen sulphide, and hydrogen.
Therefore, the correct option is C) methane.
There are several valuable microorganisms that are beneficial to humans in various manners such as: