Among the following alcohols, select the one that would react fastest with conc. HCl and anhydrous ZnCl₂ is

Mixture of conc. HCl and anhydrous ZnCl₂ is a Lucas reagent and it is used to detect primary, secondary, and tertiary alcohol.

• When tertiary alcohol reacts with Lucas reagent, then it immediately forms turbidity or cloudy appearance.
• When secondary alcohol treated with Lucas reagent, then it forms turbidity or shows cloudy appearance after five minutes.
• When primary alcohol is treated with Lucas reagent, then no turbidity occurs in-fact an oily layer generates. 

Among the given compounds, 2-methyl propan-2-ol is tertiary alcohol and shows immediate reaction with Lucas reagent.