Which reaction is used to prepare $2$-hydroxybenzaldehyde from phenol?

In the given conversion,the compound $A$ is:

Out of $o-$nitrophenol and $o-$cresol,which is more acidic?

The following reaction sequence is given:
Phenol $\xrightarrow{NaOH} X$ $\xrightarrow[(ii) H^+]{(i) CO_2} Y$ $\xrightarrow{(CH_3CO)_2O/H^+} Z + CH_3COOH$
The correct statements about $Z$ from the following are:
$I$. It is $o$-hydroxybenzoic acid.
$II$. It is a non-narcotic analgesic.
$III$. It acts as antipyretic.
$IV$. It acts as antihistamine.

The acidic property of phenol can be explained when it is reacted with:

Carbolic acid is