(A) Lucas reagent is composed of anhydrous ZnCl2 and conc.HCl. This reagent is used to differentiate between primary, secondary and tertiary alcohols. (B) Clemmensen reagent is composed of anhydrous Zn−Hg∕HCl (C) Tollens' reagent is composed of [Ag(NH3)2]+ (D) In Stephen reaction, reagents such as SnCl2 and HCl are used to reduce compounds of nitrogen. Therefore, A−III,B−IV,C−II and D−I