Halogenation is a reaction in which a halogen atom (e.g., chlorine or bromine) is added to a compound. It does not involve the introduction of alkyl groups into benzene, so it is not the correct type of reaction for the given scenario.
The Friedel-Crafts acylation reaction involves the introduction of an acyl group (RCO-) onto a benzene ring using an acyl chloride in the presence of a Lewis acid catalyst, such as anhydrous aluminum chloride (AlCl3). This reaction does not introduce alkyl groups.
The correct type of reaction described in the scenario is the Friedel-Crafts alkylation reaction. In this reaction, an alkyl group is introduced onto a benzene ring using an alkyl halide in the presence of a Lewis acid catalyst, such as anhydrous aluminum chloride (AlCl3).
Sulphonation is a different type of reaction in which a sulfonic acid group (-SO3H) is introduced onto a benzene ring. It does not involve the introduction of alkyl groups, so it is not the correct type of reaction for the given scenario.
The correct type of reaction in which alkylbenzene is formed when benzene is treated with an alkyl halide in the presence of anhydrous aluminum chloride is C. Friedel-Crafts alkylation reaction.