$1.\,\,\,\begin{array}{*{20}{c}}
{C{H_3} - C - {O^ - }} \\
{\,\,\,||} \\
{\,\,\,O}
\end{array}$ $2.\,\,CH_3O^-$ $3.\,\,CN^-$
$(A)\, CH_3 - CH_2 - C \equiv C^-$ $(B) \,CH_3 -CH_2 - S^-$
$(C) \,CH_3 - CH_2 - CO^-_2$ $(D)\, CH_3 -CH_2 - O^-$