Consider the following reaction
$$
\text { Propanal }+ \text { Methanal }=\xrightarrow[\substack{\text { (iii)s } \\ \text { (ii) } \mathrm{NaCN}^2 \mathrm{Na}}]{\text { (i) di.N } \mathrm{NaOH}} \underset{\left(\mathrm{C}_5 \mathrm{H}_8 \mathrm{O}_3\right)}{\text { Product B }}
$$
The correct statement for product $B$ is. It $\mid$ is