Cumene on oxidation in air gives a compound,$X$. This on reaction with dilute acid gives $Y$ and $Z$. $Y$ reacts with sodium metal and not $Z$. What is $Z$ ?

The reactivity of compound $Z$ with different halogens under appropriate conditions is given below:
(Image of reaction: $Z$ ($3$-tert-butylphenol) reacts with $X_2$ to give mono-halo derivative for $X_2 = I_2$,di-halo for $X_2 = Br_2$,and tri-halo for $X_2 = Cl_2$)
The observed pattern of electrophilic substitution can be explained by:
$A$. The steric effect of the halogen
$B$. The steric effect of the tert-butyl group
$C$. The electronic effect of the phenolic group
$D$. The electronic effect of the tert-butyl group

In the reaction shown,the electrophile involved is:

When heated with $NH_3$ under pressure alone or in the presence of zinc chloride,phenols are converted into:

Sodium phenoxide when heated with $CO_2$ under pressure at $125\,^{\circ}C$ yields a product which on acetylation produces $C$. The major product $C$ would be

Which of the following is most acidic?