Concept:Decarboxylation removes −COOH as carbon(IV)oxide, leaving the remaining alkyl group bonded to hydrogen.Explanation:Ethanoic acid is CH3COOH.When it undergoes decarboxylation, CO2 is removed from the carboxyl group.The remaining group is CH3, which combines with a hydrogen atom to form CH4, methane.Answer:Methane (Option A).