Which of the following represents the structure of the methyl hemiacetal of formaldehyde?

The reaction of $1-(\text{aminomethyl})cyclohexan-1-ol$ with $NaNO_2/HCl$ gives $A$. Identify $A$.

Identify $R', R''$ and $R'''$ for the following reaction: $R'R''C=O \xrightarrow{(i) R'''MgX, (ii) H_2O} 2-methylbutane-2-ol$

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

Compounds $P$ and $R$ upon ozonolysis produce $Q$ and $S$,respectively. The molecular formula of $Q$ and $S$ is $C_8H_8O$. $Q$ undergoes Cannizzaro reaction but not haloform reaction,whereas $S$ undergoes haloform reaction but not Cannizzaro reaction.
$(i)$ $P \xrightarrow[\text{ii) } Zn / H_2O]{\text{i) } O_3 / CH_2Cl_2} \underset{(C_8H_8O)}{Q}$
$(ii)$ $R \xrightarrow[\text{ii) } Zn / H_2O]{\text{i) } O_3 / CH_2Cl_2} \underset{(C_8H_8O)}{S}$
The option$(s)$ with a suitable combination of $P$ and $R$,respectively,is(are):

The order of reactivity of phenyl magnesium bromide $(PhMgBr)$ with the following compounds is: