Concept:Biotechnology produces fuels from biological materials; ethanol is a common biofuel.Explanation:Ethanol is obtained by fermentation of sugars using microorganisms.This makes it a product of biotechnology.Ethanol burns readily and can replace or be blended with petrol.Butane and ethene are mainly petroleum products, not biotechnological fuels.Propanol is not typically produced on a large scale as a biofuel.Answer:B. Ethanol