The correct option is (a) Potassium chlorate
To explain I would say: In the reaction of 2-Aminoanthraquinone from 2- Chloroanthraquinone, by the use of potassium chlorate and ammonium nitrate as oxidants, it is possible to obtain directly a 2-aminoanthraquinone of 97.5-98.5 per cent purity.