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: Medicine
Most common myeloproliferative disorder is 
Select and explain. 
A. Polycythemia rubra vera, B. CML, C. CLL, D. Myelofibrosis
A: Polycythemia rubra vera
Answer: A: Polycythemia rubra vera 
Explanation: Examples of Myeloproliferative diseases are Polycythemia rubra vera, Myelofibrosis, and Essential thrombocytopenia. Here CML and CLL are not Myeloproliferative diseases and out the rest two Polycythemia is more common. Reference : Davidaon, 23rd Edition, page no : 969.