The final product of the given reaction is?

The total number of $sp^2$ hybridised carbon atoms in the major product $P$ (a non-heterocyclic compound) of the following reaction is. . . . . . .

In the reaction sequence: $CH_3-CHO$ $\xrightarrow{HCN, OH^{-}} (A)$ $\xrightarrow{H_2O/H^{+}, \Delta} \text{Product}$. The product will be:

The final product $A$ formed in the following multistep reaction sequence is:

$A$ in the above reaction is:

The molecular formula of compound $A$ is $C_2Cl_3OH$. It reduces Fehling's solution and on oxidation gives a monocarboxylic acid $B$. Compound $A$ is obtained by the reaction of chlorine with ethyl alcohol. What is $A$?