The correct option is D Methane
Production of biogas
Methanogenic bacteria like Methanobacterium are bacteria used in digesters of the biogas plant where they act on organic matter, anaerobically converting it to a mixture of inflammable gases that forms biogas.
Components of biogas
The major component of biogas is methane (50-75%) and carbon dioxide (25-50%). Trace amounts of hydrogen sulphide, nitrogen and hydrogen are also present.
Final answer
(A) Methane