This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Anatomy
[{'content': 'Iron overload occurs in all except \nSelect and explain. \nA. Thalassemia, B. Myelodysplastic syndrome, C. Polycythemia vera, D. Sideroblastic anemia', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ref Harrison 19 th ed pg 626, 673 Increased erythropoietin leads to increased haematopoasis and an increased demand for iron producing a state of iron deficiency. Polycythemia vera being a state of increased erythropoietin is a cause of iron deficiency rather than iron overload.', 'role': 'assistant'}]