
$(A)$ $\begin{matrix}
O\,\,\,\,\,\,\,\,\,\, \\
||\,\,\,\,\,\,\,\,\,\,\,\, \\
R-C-NHBr \\
\end{matrix}$ $(B)$ $R-NH-Br$
$(C)$ $R-N=C=O$ $(D)$ $\begin{matrix}
\,\,\,\,O\,\,\,\,\,\,\,\,\,\, \\
\,\,\,\,\,\,||\,\,\,\,\,\,\,\,\,\,\,\, \\
R-C-NB{{r}_{2}} \\
\end{matrix}$



$(A)$ $X = COOCH _3, Y = H _2 /$ Ni/heat
$(B)$ $X = CONH _2, Y = H _2 /$ Ni/heat
$(C)$ $X = CONH _2, Y = Br _2 / NaOH$
$(D)$ $X = CN , Y = H _2 /$ Ni/heat


