b
\(\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,\,\,\,\,C{H_3}} \\
{\,\,\,\,\,\,|} \\
{C{H_3} - C = O}
\end{array}\) + \(C{H_3}COC{H_3}\) \( \to \) \(\mathop {\begin{array}{*{20}{c}}
{\,C{H_3}\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,O\,\,\,} \\
{\,\,\,|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,||\,\,\,\,} \\
{C{H_3} - C - C{H_2} - C - C{H_3}} \\
{\,\,|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{OH\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}
\end{array}}\limits_{{\text{4 - Hydroxy - 4 - methyl - 2 - pentanone}}} \)