Step 1: Exchange transfusion is a procedure in which the patient's blood is slowly removed in small aliquots and replaced with fresh donor blood. It is most often performed in neonates with severe hyperbilirubinaemia or haemolytic disease of the newborn.
Step 2: Because the goal is to replace both the cellular and plasma components and to remove bilirubin, antibodies and toxins, fresh whole blood is the product of choice. Whole blood supplies red cells together with plasma in physiological proportions.
Step 3: Serum and EPP do not provide red cells, so they cannot correct anaemia or remove sensitised cells. Packed cells lack plasma and would not replace the volume or remove plasma bound substances effectively, so option a, whole blood, is correct.