
The activating effect is so strong in a polar solvent like water that electrophilic aromatic substitution occurs at all available ortho and para positions simultaneously.
$$\text{}$$Intermediate 1: 2,4,6-tribromoanilin
Sodium nitrite and hydrochloric acid at low temperatures ($$0-5^\circ\text{C}$$).Reaction: This converts the primary aromatic amine group ($$-\text{NH}_2$$) into a stable diazonium salt group ($$-\text{N}_2^+\text{Cl}^-$$)
Hypophosphorous acid ($$\text{H}_3\text{PO}_2$$) and water.
$$\text{}$$Reaction: This is a classic reduction reaction where the diazonium group ($$-\text{N}_2^+$$) is completely replaced by a hydrogen atom ($$\text{H}$$), releasing nitrogen gas ($$\text{N}_2$$) and turning $$\text{H}_3\text{PO}_2$$ into phosphorous acid ($$\text{H}_3\text{PO}_3$$).
$$\text{}$$Outcome: The ring loses its nitrogen functional group entirely, leaving behind only the substituted bromine atoms.
Hence, Option C is correct.