p-Aminoazobenzene, a yellow dye, is produced in 

Coupling reaction

The correct answer is option 3. Coupling reaction.

p-Aminoazobenzene, a yellow dye, is produced in a coupling reaction. In a coupling reaction, an aromatic diazonium salt reacts with an aromatic amine to form an azo compound. In the case of p-aminoazobenzene, the diazonium salt is typically derived from aniline, and it reacts with an aromatic amine to form the azo compound, p-aminoazobenzene. This reaction is commonly used in the synthesis of azo dyes, where the choice of aromatic amine determines the color of the dye.