**Core Concept**
The question is testing the student's understanding of neonatal jaundice, specifically the differentiation between hemolytic and non-hemolytic causes. Neonatal jaundice is a common condition characterized by elevated bilirubin levels in newborns, which can be due to hemolysis, liver immaturity, or other causes.

**Why the Correct Answer is Right**
The presence of nucleated RBCs, spherocytes, and a high reticulocyte count in the peripheral smear, along with a high unconjugated bilirubin level, suggests hemolytic disease. The high reticulocyte count indicates an increased production of RBCs to compensate for the hemolysis. The presence of spherocytes, which are RBCs that have lost their central pallor due to membrane loss, is a characteristic feature of hereditary spherocytosis. The high unconjugated bilirubin level and the absence of significant anemia (Hemoglobin 14 g/dl) suggest that the hemolysis is not severe. The presence of nucleated RBCs in the peripheral smear can be seen in conditions that stimulate the bone marrow to release nucleated RBCs into the circulation, such as hemolytic anemia.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not explain the presence of spherocytes and nucleated RBCs in the peripheral smear.
**Option B:** This option is incorrect because it does not account for the high reticulocyte count and the presence of spherocytes.
**Option C:** This option is incorrect because it does not explain the presence of nucleated RBCs and spherocytes in the peripheral smear.

**Clinical Pearl / High-Yield Fact**
Hereditary spherocytosis is a genetic disorder characterized by the production of abnormal RBCs that are prone to hemolysis. It is the most common cause of hereditary hemolytic anemia. The presence of spherocytes, nucleated RBCs, and a high reticulocyte count in the peripheral smear is a key diagnostic clue.

**Correct Answer: D. Hereditary Spherocytosis**