Correct Answer - A
For a given HX, the reactivity of alcohol depends on the stability of carbocation formed. The order of stability of carbocation is Benzyl `gt 3^(@) gt 2^(@) gt 1^(@)`.
The order of reactivity of alcohols is therefore
`{:(I,gt,II ,gt,III ,gt,IV),(("Benzyl"),,(3^(@)),,(2^(@)),,(1^(@))):}`