Of the following alcohols, the one that would react fastest with $\mathrm{conc}. \mathrm{HCl}$ and anhydrous ${\mathrm{ZnCl}}_{2_{ }}$ is :

$\mathrm{R}-\mathrm{OH}+\mathrm{HCl}\underset{{\mathrm{ZnCl}}_2}{\overset{\mathrm{anhydrous}}{\to }}\mathrm{R}-\mathrm{Cl}+{\mathrm{H}}_2\mathrm{O}.$This is the reaction of alcohols with Lucas reagent. It involves C – O Cleavage.
Rate of reactivity …….   ${\mathrm{R}}_3\mathrm{COH}>{\mathrm{R}}_2\mathrm{CHOH}>{\mathrm{RCH}}_2\mathrm{OH}$

$3^0$-alcohols give immediate turbidity
$2^0$-alcohols give turbidity in few minutes
$1^0$-alcohols do not give turbidity at room temperature.

${\left({\mathrm{CH}}_3\right)}_3\mathrm{C}-\mathrm{OH}$ is a $3^0$$\mathrm{alcohol}$

$3^0$-alcohols which gives immediate turbidity.