What is the possible product $(P)$ in the following reaction?

Given below are two statements:
Statement $I$: $2, 6$-diethylcyclohexanone and $6$-methyl-$2$-$n$-propylcyclohexanone are metamers.
Statement $II$: $2, 2, 6, 6$-tetramethylcyclohexanone exhibits keto-enol tautomerism.

Identify the compound that exhibits tautomerism:

$CH_3-C \equiv CH \xrightarrow[dil. H_2SO_4]{Hg^{+2}} (P)$,$CH_3-C \equiv CH \xrightarrow[(2) H_2O_2]{(1) BH_3, THF} (Q)$. $P$ and $Q$ can be differentiated by

The correct order of rate of reaction toward nucleophilic addition reaction for the following compounds is:
$(a)$ $p-NO_2-C_6H_4-CHO$
$(b)$ $C_6H_5-CHO$
$(c)$ $p-OMe-C_6H_4-CHO$
$(d)$ $CH_3-CO-CH_2CH_3$
$(e)$ $C_6H_5-CO-C_6H_5$

Which of the following on reaction with Grignard reagent followed by hydrolysis forms a secondary alcohol?