Correct choice is (a) Sewage Sludge
To elaborate: Sewage Sludge is produced during primary and secondary treatment phases and are usually sticky and has pathogens, so, it is both inorganic and organic, whereas, Liquid crystalline and Semi crystalline are optically active polymer that can activate in response to heat, light, electrical field etc. and hence, is not is inorganic or organic and natural gas is usually a hydrocarbon which is non-renewable.