What is the product formed when salicylic acid is treated with zinc dust?

An organic compound with the molecular formula $C_6H_6O$ dissolves in $NaOH$, gives a characteristic colour with neutral $FeCl_3$ and on treatment with bromine water gives a tri-bromo derivative. Which is that compound among the following?

The major product of the following reaction is:

The correct order of acid strength of the following compounds is:
$A$. Phenol
$B$. $p$-Cresol
$C$. $m$-Nitrophenol
$D$. $p$-Nitrophenol

Decarboxylation of sodium salicylate with soda lime forms

Which of the following has the highest $pK_{a}$ value?