In alkaline medium, phenol forms phenoxide ion, which is strongly activating and directs electrophilic substitution at ortho and para positions. Benzenediazonium ion acts as an electrophile in azo coupling, and para substitution is favored due to less steric hindrance. The major product is therefore p-hydroxyazobenzene, an azo dye intermediate with -N=N- linkage between aromatic rings. The other options correspond to unrelated reaction pathways.