b
\(\begin{matrix}
   O  \\
   ||  \\
   N{{H}_{2}}-C-N{{H}_{2}}  \\
\end{matrix}\) \(\xrightarrow[\text{acid or base}]{\text{hydrolysis}}\) \(C{{O}_{2}}+2{{H}_{3}}\xrightarrow{{{H}_{2}}O}\underset{\text{Carbonic acid}}{\mathop{{{H}_{2}}C{{O}_{3}}}}\,\)

Note: The enzyme urease (occurs in soyabean) brings about the same change