a
The reagent which can convert- \(-\mathrm{CONH}_{2}\) group into \(-\mathrm{NH}_{2}\) group is used for this reaction. Among the given reagents only NaOH/ Br _2 converts - \(\mathrm{CONH}_{2}\) group to \(-NH_{2}\) group, thus it is used for converting acetamide to methylamine. This reaction is called Hoffman bromide reaction.

\(\mathrm{CH}_{3} \mathrm{CONH}_{2}+\mathrm{NaOH}+\mathrm{Br}_{2} \rightarrow\mathrm{CH}_{3} \mathrm{NH}_{2}+\mathrm{NaBr}+\mathrm{Na}_{2} \mathrm{CO}_{3}+\mathrm{H}_{2} \mathrm{O}\)