$H_2C = CH - CH_2 - I \xrightarrow[CC{{l}_{4}}]{HI(excess)}$
$C{H_3}COOH\xrightarrow{{LiAl{H_4}}}A\mathop {\xrightarrow{{{H^ + }}}}\limits_{443\,K} B\xrightarrow{{B{r_2}}}C\mathop {\xrightarrow{{alc.}}}\limits_{KOH} D$