Which of the following compounds will undergo decarboxylation on heating?

Considering the reaction sequence given below,the correct statement$(s)$ is(are):
$A$. $P$ can be reduced to a primary alcohol using $NaBH_4$.
$B$. Treating $P$ with conc. $NH_4OH$ solution followed by acidification gives $Q$.
$C$. Treating $Q$ with a solution of $NaNO_2$ in aq. $HCl$ liberates $N_2$.
$D$. $P$ is more acidic than $CH_3CH_2COOH$.

Maximum enol content is in

The product $(P)$ of the given reaction is:

Ethanoic acid $+$ $3$-methylbutan-$1$-ol $\underset{\text{traces } H_2SO_4}{\longleftrightarrow} (A)$; Compound $(A)$ is

Match the reactions given in Column-$I$ with the appropriate reagents in Column-$II$.
| Column-$I$ (Reaction) | Column-$II$ (Reagent) |
| :--- | :--- |
| $(A)$ $2CH_3COOH \rightarrow (CH_3CO)_2O$ | $(i)$ $(I) NH_3, (II) \Delta, -H_2O$ |
| $(B)$ Phthalic acid $\rightarrow$ Phthalamide | $(ii)$ $(I) Br_2 / \text{red phosphorous}, (II) H_2O$ |
| $(C)$ $CH_3CH_2COOH \rightarrow CH_3CHBrCOOH$ | $(iii)$ $Br_2 / FeBr_3$ |
| $(D)$ Benzoic acid $\rightarrow$ $m$-Bromobenzoic acid | $(iv)$ $H^+, \Delta \text{ OR } P_2O_5, \Delta$ |