b
\(\begin{array}{*{20}{c}}
{\,\,\,C{H_3}\,} \\
{|\,\,\,\,} \\
{C{H_3} - C - OC{H_3}} \\
{|\,\,\,\,} \\
{\,\,C{H_3}}
\end{array}\, + \,HI\, \to \,\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,C{H_3}} \\
{\,\,\,\,\,\,\,\,\,|} \\
{C{H_3} - C - I} \\
{\,\,\,\,\,\,\,|} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,C{H_3}}
\end{array}\, + \,C{H_3}OH\)