Step 1: Identify the reagents for each reaction. 1. Finkelstein reaction (A) involves halogen exchange, where alkyl chlorides or bromides react with sodium iodide in acetone to form alkyl iodides. The reagent for this reaction is \( \text{NaI/Acetone} \), which matches with \( P \). 2. Swarts reaction (B) is used to prepare alkyl fluorides from alkyl chlorides or bromides using fluorinating agents like \( \text{SbF}_3 \). The reagent for this reaction is \( \text{SbF}_3 \), which matches with \( S \). 3. Fittig reaction (C) involves the coupling of aromatic halides with alkyl halides in the presence of sodium metal in dry ether, which corresponds to the reagent \( \text{Na/THF} \), which matches with \( Q \). 4. Sandmeyer reaction (D) is used for the substitution of diazonium salts with cuprous halides, such as \( \text{Cu}_2\text{Cl}_2/\text{HCl} \), which matches with \( R \). Step 2: Conclusion.
Thus, the correct matching is: \[ A → P ; B → S ; C → Q ; D → R \] (B) A → P ; B → S ; C → Q ; D → R.