Correct answer is (c) Methane formation
To elaborate: Methane formation or methanogenesis is a process in anaerobic fermentation. Hydrolysis converts organic matter; Acidification forms acetic acid and methanogenesis leads to methane. Since, this is an end product, it doesn’t raise the technical expenditure. Whereas, Noise, germs, odor and dust can elevate the growth of technical expenditure if their emissions are not controlled.