In the reaction $CH_3CH_2OH \xrightarrow{OH^-} CH_3CHO$,which carbon atom undergoes oxidation?

Given below are two statements: Consider the following reaction: $R_2C=O + H_2O \rightleftharpoons R_2C(OH)_2$.
Statement $I$: In the case of formaldehyde $(HCHO)$,$K_{eq}$ is about $2280$,due to small substituents,hydration is faster.
Statement $II$: In the case of trichloroacetaldehyde $(CCl_3CHO)$,$K_{eq}$ is about $2000$ due to the $-I$ effect of $-Cl$ atoms.
In the light of the above statements,choose the correct answer from the options given below:

$A$ $(C_3H_6O)$ $\xrightarrow{NaCN/H_2SO_4}$ cyanohydrin of $A$. If the cyanohydrin is optically active,then the possible structure of $A$ is:

In the following reaction, the major product $(H)$ is

$CH_3CHO$ $\xrightarrow[5\,^{\circ}C]{10\%\,NaOH}$ $\xrightarrow[\Delta]{}$ $\xrightarrow[Ni]{H_2} (A)$; Product $(A)$ of the reaction is

The general order of reactivity of carbonyl compounds for nucleophilic addition reactions is