Option (iii) is the answer.

The Lucas reagent is a combination of concentrated HCl and dry anhydrous , and the reaction is known as the Lucas test. It’s used to figure out whether a particular alcohol is primary, secondary, or tertiary. Because the carbocation is generated as an intermediate in this reaction, the pace of the reaction is determined by the stability and ease of carbocation production, which is the slow step of the process. Because the hyperconjugation effect is the most important factor in tertiary carbocation stability. As a result of the S N 1 mechanism, the sequence of reactivity is tertiary alcohol>secondary alcohol.