$2(CHO-COOH) \xrightarrow{NaOH} CH_2OH-COOH + HOOC-COONa$. This reaction is:

$p$-cresol reacts with chloroform in an alkaline medium to give compound $A$,which adds hydrogen cyanide to form compound $B$. The latter,on acidic hydrolysis,gives a chiral carboxylic acid. The structure of the carboxylic acid is:

$CH_3-CO-CH_2-COOH$ $\xrightarrow{\Delta} X$ $\xrightarrow[OH^-]{HCN} Y$,$Y$ is:

Methyl ketone group is identified by

Given below are two statements: Statement $I$: The condensation reaction between $CH_{3} - CH = O$ and $H_{2}N - NH - C(=O) - NH_{2}$ under optimum pH will produce $CH_{3} - CH = N - N(H) - C(=O) - NH_{2}$. Statement $II$: The molecule, $Ph - CH(OH)(OCH_{3})$ will generate $Ph - CH = O$ in the presence of dilute acid. In the light of the above statements, choose the correct answer from the options given below:

In the following reactions,$P, Q, R$,and $S$ are the major products.
The correct statement$(s)$ about $P, Q, R$,and $S$ is(are):
$(A)$ Both $P$ and $Q$ have asymmetric carbon$(s)$.
$(B)$ Both $Q$ and $R$ have asymmetric carbon$(s)$.
$(C)$ Both $P$ and $R$ have asymmetric carbon$(s)$.
$(D)$ $P$ has asymmetric carbon$(s)$,$S$ does not have any asymmetric carbon.