A male infant was found to be jaundiced 12 hours after birth. At 36 hours of age, his serum bilirubin was 18 mg/dL, hemoglobin concentration was 12.5 g/dL, and reticulocyte count 9%. Many nucleated RBCs and some spherocytes were seen in the peripheral blood smear. The differential diagnosis should include which of the following?
a) Hemolytic disease of the newborn
b) Physiologic jaundice
c) Gilbert syndrome
d) Crigler-Najjar syndrome