Which from following compounds is obtained when acetamide is warmed with bromine and excess conc. $\mathrm{KOH}_{(\mathrm{aq})}$ solution?

The Hofmann bromamide degradation reaction converts primary amides to primary amines with one fewer carbon atom. For acetamide, $\mathrm{CH}_3\mathrm{CONH}_2$, the reaction proceeds as follows: $\mathrm{CH}_3\mathrm{CONH}_2 + \mathrm{Br}_2 + 4\mathrm{KOH} \xrightarrow{\text{warm}} \mathrm{CH}_3\mathrm{NH}_2 + \mathrm{K}_2\mathrm{CO}_3 + 2\mathrm{KBr} + 2\mathrm{H}_2\mathrm{O}$, yielding methylamine.

Examining the options:
A) $\mathrm{CH}_4$
B) $\mathrm{CH}_3\mathrm{COOH}$
C) $\mathrm{CH}_3\mathrm{CH}_2\mathrm{NH}_2$
D) $\mathrm{CH}_3\mathrm{NH}_2$

Only methylamine, with one carbon, matches the product structure and carbon count reduction. The correct answer is $\boxed{\text{D}}$.