\[\begin {array} {1 1} (a)\;CH_3COCH_3,CH_3CH_O \\ (b)\;C_2CH_5CO_2H,CH_3CO_2CH_3 \\ (c)\;C_2H_5CO_2H,CHCO_2C_2H_5 & \\ (d)\;CH_3CO_2,CH_3CHO \end {array}\]