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
Following are features of polycythemia rubra vera except - 
Select and explain. 
A. Increased red cell mass, B. Normal aerial oxygen sturation, C. High leucocyte alkaline phosphatase score, D. None
D: None
Answer: D: None 
Explanation: <p>Polycythaemia rubra vera results in increased red cell mass,aerial oxygen saturation >92%, & raised neutrophil alkaline phosphatase scores.</p><p>Reference :Harsh mohan textbook of pathology sixth editionpg no 359.</p>