Wurtz–Fittig reaction takes place between

R–X and Ar–X

The answer is (2) R–X and Ar–X.

The Wurtz–Fittig reaction is a chemical reaction that combines an alkyl halide (R–X) and an aryl halide (Ar–X) to form a substituted aromatic compound. The reaction is named after Charles Adolphe Wurtz and Wilhelm Rudolph Fittig, who independently discovered the reaction in the 1850s.