What are $\underline{A},\underline {B}, \underline {C}$ in the following reactions ?

Question

	$\underline{A}$	$\underline{B}$	$\underline{C}$
(1) (2) (3) (4)	$C_2H_6$ $(CH_3CO)_2$ $CH_3COCH_3$ $CH_3COCH_3$	$CH_3COCH_3$ $C_2H_6$ $C_2H_6$ $(CH_3CO)_2O$	$(CH_3CO)_2O$ $CH_3COCH_3$ $(CH_3C_O)_2O$ $C_2H_6$