An organic compound having molecular mass 60 is found to contain $\mathrm{C}=20 \%, \mathrm{H}=$ $6.67 \%$ and $\mathrm{N}=46.67 \%$ while rest is oxygen. On heating it gives $\mathrm{NH}_3$ alongwith a solid residue. The solid residue give violet colour with alkaline copper sulphate solution. The compound is

• A

  $\mathrm{CH}_3 \mathrm{NCO}$
• B

  $\mathrm{CH}_3 \mathrm{CONH}_2$
• Correct answer
  C

  $\left(\mathrm{NH}_2\right)_2 \mathrm{CO}$
• D

  $\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CONH}_2$

Hence, the correct answer is option: 'C'.