$(I)$ $C{H_2} = CH\mathop C\limits^ + HC{H_3}$
$\begin{array}{*{20}{c}}
{{\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,C{H_3}} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|\,\,} \\
{(II)\,\,\,\,\,\,\,\,\,\,C{H_2} = C - \mathop {{\text{ }}C}\limits^ + {H_2}}
\end{array}$
$(III)$ $C{H_3}CH = CH\mathop C\limits^ + {H_2}$
$(A)\, CH_3 - CH_2 - C \equiv C^-$ $(B) \,CH_3 -CH_2 - S^-$
$(C) \,CH_3 - CH_2 - CO^-_2$ $(D)\, CH_3 -CH_2 - O^-$