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: Medicine
[{'content': 'Pancytopenia with cellular marrow is seen in all, except: \nSelect and explain. \nA. Megaloblastic anemia, B. Myelodysplasia, C. Paroxysmal nocturnal hemoglobinuria, D. G6 PD deficiency', 'role': 'user'}, {'content': "Answer: D \nExplanation: G6PD deficiency is not associated with pancytopenia and a cellular marrow. So G6PD is the single best answer of choice. Ref: Harrison's Principles of Internal Medicine, 16th Edition, Page 617; Manual of Practical Medicine By R Alagappan, 3rd Edition, Page 335", 'role': 'assistant'}]