c
\((c)\) \(\begin{matrix}
   \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,C{{H}_{3}}  \\
   \,\,\,\,\,\,\,\,\,\,\,\,\,|  \\
   C{{H}_{3}}-CH-C-C{{H}_{3}}  \\
   |\,\,\,\,\,\,\,\,\,\,\,\,\,|  \\
   \,\,\,\,OH\,\,\,\,\,\,C{{H}_{3}}  \\
\end{matrix}\) \(\xrightarrow{{{H}_{2}}S{{O}_{4}}}\)

\(\underset{{{2}^{o}}\,carbonium\,ion}{\mathop{\begin{matrix}
   \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,C{{H}_{3}}  \\
   \,\,\,\,\,\,\,\,\,\,\,\,\,|  \\
   C{{H}_{3}}\overset{+}{\mathop{-C}}\,H-C-C{{H}_{3}}  \\
   \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,  \\
   \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,C{{H}_{3}}  \\
\end{matrix}}}\,\) \(+O{{H}^{-}}\xrightarrow[\operatorname{Re}arrangement]{Methyl\,shift}\)

\(\underset{2,3-dimethyl-2-Butene\,[Most\,synnetrial\,structure]}{\mathop{\begin{matrix}
   \,\,\,\,\,\,\,C{{H}_{3}}\,\,C{{H}_{3}}  \\
   |\,\,\,\,\,\,\,\,\,|  \\
   C{{H}_{3}}-C=C-C{{H}_{3}}  \\
\end{matrix}}}\,\) \(\xleftarrow[-{{H}^{+}}]{}\) \(\underset{{{3}^{o}}\,Carbonium\,ion\,(More\,stable)}{\mathop{\begin{matrix}
   \,\,\,\,\,\,\,\,C{{H}_{3}}\,\,\,C{{H}_{3}}  \\
   \,\,|\,\,\,\,\,\,\,\,\,\,\,\,|  \\
   C{{H}_{3}}-CH-\underset{+}{\mathop{C}}\,-C{{H}_{3}}  \\
\end{matrix}}}\,\)