This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'Pancytopenia with a cellular marrow is seen in all except \nSelect and explain. \nA. PNH, B. Megaloblastic anemia, C. Myelodysplastic syndrome, D. Congenital dyserythropoietic anemia', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Congenital dyserythropoietic anemia', 'role': 'assistant'}]