Which of the following will show the haloform reaction?

Product $(A)$ of the reaction is

Formaldehyde can be distinguished from acetaldehyde by the use of

Identify the products $A$,$B$,and $C$ in the following reaction sequence:
$C_6H_5CONH_2$ $\xrightarrow{P_2O_5, \Delta} A$ $\xrightarrow[(ii) H_2O]{(i) DIBAL-H} B$
$A \xrightarrow[(ii) H_3O^+, \Delta]{(i) (CH_3CO)_2O/CH_3COONa} C$

How can benzyl alcohol be obtained from benzaldehyde?

$3-\text{Hydroxybutanal}$ is formed when $X$ reacts with $Y$ in dilute $Z$ solution. What are $X, Y$ and $Z$? $(X, Y, Z)$