Concept:Carboxylic acid is reduced to alcohol, then converted to alkyl halide, and finally dehydrohalogenated to alkene.Explanation:CH3COOHLiAlH4CH3CH2OH (X, ethanol).CH3CH2OHPCl5CH3CH2Cl (Y, ethyl chloride).CH3CH2Clalcoholic KOHCH2=CH2 (Z, ethene).Answer:Product Z is ethene, so the correct option is C.