A.CH3-CHO B.CH3-CO-CH3 C.CH3-CHOH-CH3 D.CH3-O-CH2-CH3
A.C-C>C-N>C-O B.C-N>C-O>C-C C.C-C>C-O>C-N D.C-O>C-N>C-C
A.C-H B.N-H C.O-H D.F-H