Number of compounds from the following which will not dissolve in cold ${\mathrm{NaHCO}}_3$ and $\mathrm{NaOH}$ solutions but will dissolve in hot $\mathrm{NaOH}$ solution is _____ .

Consider the following reaction

$$\begin{gathered} \mathrm{Propanal}+\mathrm{Methanal}=\underset{\left(\mathrm{ii}\right) \mathrm{\Delta } \\ \left(\mathrm{iii}\right) \mathrm{NaCN} \\ \left(\mathrm{iv}\right) {\mathrm{H}}_3{\mathrm{O}}^{+}}{\overset{\left(\mathrm{i}\right) \mathrm{dil}. \mathrm{NaOH}}{\to }}\mathrm{P}\underset{\left({\mathrm{C}}_5{\mathrm{H}}_8{\mathrm{O}}_3\right)}{\mathrm{roduct} \mathrm{B}} \end{gathered}$$

The correct statement for product $B$ is. It is

 The number of molecules which gives haloform test among the following molecules is :

The structures of major products $\mathrm{A},\mathrm{B}$ and $\mathrm{C}$ in the following reaction are sequence.