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
Iron overload occurs in all, except - 
Select and explain. 
A. Thallassemia, B. Myelodysplastic syndrome, C. Polycythemia vera, D. Sideroblastic anaemia
C: Polycythemia vera
Answer: C: Polycythemia vera 
Explanation: None