Under what reaction conditions (acidic/basic),the coupling reaction of aryldiazonium chloride with aniline is carried out?

(A) The coupling reaction of aryldiazonium salts with aniline is carried out under mildly acidic conditions ($pH$ $4-5$).
In strongly basic conditions,the diazonium salt is converted into diazohydroxide or diazoate,which are not electrophilic and thus do not undergo coupling.
In highly acidic conditions,aniline is protonated to form the anilinium ion $(C_6H_5NH_3^+)$. The anilinium ion is not nucleophilic because the lone pair on the nitrogen atom is no longer available for the electrophilic attack on the diazonium salt.
Therefore,to maintain a sufficient concentration of nucleophilic aniline while keeping the diazonium salt electrophilic,the reaction is performed at a mild $pH$ of $4-5$.