A child presents with complaints of oliguria,abdominal distension and diarrhoea.On examination there is deep jaundice.Hepatomegaly was present measuring 4 cm below the costal margin.Conjugated bilirubin in blood was 38mg/dL,and there was urine urobilinogen and bile pigments.Hemoglobin was 4mg/dL and serum creatinine was 3mg/dL.Which of the following tests is of least importance to diagnose this case

• A. G-6-PD level in blood
• B. Serum ceruloplasmin
• C. Reticulocyte count
• D. Leptospiral antibody level