Urea reacts with water to form $\mathrm{A}$ which will decompose to form $\mathrm{B}$. $\mathrm{B}$ when passed through ${\mathrm{Cu}}^{2+}\left(\mathrm{aq}\right)$, deep blue colour solution $\mathrm{C}$ is formed. What is the formula of $\mathrm{C}$ from the following?

• Correct answer
  A

  ${\left[\mathrm{Cu}{\left({\mathrm{NH}}_3\right)}_4\right]}^{2+}$
• B

  $\mathrm{Cu}{\left(\mathrm{OH}\right)}_2$
• C

  ${\mathrm{CuCO}}_3·\mathrm{Cu}{\left(\mathrm{OH}\right)}_2$
• D

  ${\mathrm{CuSO}}_4$

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