$A\xrightarrow[(ii)\;H_3O^+]{(i)\;CH_3MgBr}B\xrightarrow[573\;K]{Cu}2-$methyl $2-$butene
$A$ માં કાર્બનની દળની ટકાવારી ........ હશે.
$(I)$ $\begin{array}{*{20}{c}}
O \\
{||} \\
{Ph\, - C - Ph}
\end{array}$
$(II)$ $\begin{array}{*{20}{c}}
{\,\,\,\,O} \\
{\,\,\,\,||} \\
{C{H_3} - C - H}
\end{array}$
$(III)$ $\begin{array}{*{20}{c}}
O \\
{||} \\
{C{H_3} - C - C{H_3}}
\end{array}$
is