Explanation:
(c) \(3C{H_2} = C{H_2} + 2KMn{O_4} + 4{H_2}O \to \)
$\mathop {3\begin{array}{*{20}{c}}
{C{H_2} - OH} \\
{|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,} \\
{C{H_2} - OH}
\end{array}}\limits_{{\text{Glycol}}} $ $ + {\mkern 1mu} 2KMn{O_2} + 2KOH$