To solve this problem, we need to identify the reaction that converts acetamide to methanamine.$\newline$Let's analyze each option:$\newline$• Option 1: Hoffmann hypobromamide reaction$\newline$ - This reaction involves the conversion of an amide to an amine with one less carbon atom.$\newline$ - The general reaction is:$\newline$ RCONH$_2 \xrightarrow{Br_2, NaOH} {RNH}_2 + {CO}_2 \newline$ - For acetamide $(CH_3{CONH}_2)$, the reaction is:$\newline CH_3{CONH}_2 \xrightarrow{Br_2, NaOH}$CH$_3$NH$_2 +$CO$_2 \newline$ - This correctly converts acetamide to methanamine.$\newline$• Option 2: Stephens reaction$\newline$ - This is a reduction reaction used to convert nitriles to aldehydes, not applicable here.$\newline$• Option 3: Gabriel's phthalimide synthesis$\newline$ - This is used to synthesize primary amines from alkyl halides, not directly applicable for amides.$\newline$• Option 4: Carbylamine reaction$\newline$ - This reaction is used to synthesize isocyanides from primary amines, not applicable for converting amides.$\newline$Therefore, the correct reaction for converting acetamide to methanamine is the Hoffmann hypobromamide reaction.$\newline$This corresponds to Option 1.