In biogas plants,when is methane gas produced in large quantities?

The highest amount of gas present in biogas is $.......$.

Study the following flow chart of biogas production and select the correct option for $A, B$ and $C$.
Stage $III$: $C$
Stage $II$: Organic acids $\xrightarrow{B}$ $C$
Stage $I$: Soluble compounds or monomers $\xrightarrow{A}$ Organic acids
(Note: The flow chart shows: Proteins,Fats,Cellulose,Hemicellulose $\rightarrow$ Soluble compounds or monomers $\xrightarrow{A}$ Organic acids $\xrightarrow{B}$ $C$)

Which one of the following is the $CORRECT$ order of conversion of waste materials during biogas formation?

During biogas production,acetic acid is transformed into the final product by the enzymes of:

Compost manure is formed from