$I.\,\,C{H_3}C{H_2}C{H_2}C{H_2}OH\,$
$II.\,\,C{H_3} C{H_2}C{H_2}CHO\,$
$ III.\,\,C{H_3}C{H_2}C{H_2}COOH\,$

$\begin{array}{*{20}{c}}
{{C_2}{H_5}MgBr + {H_2}C - C{H_2}\xrightarrow{{{H_2}O}}} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\backslash \,\,\,\,/} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,O}
\end{array}A$