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: Surgery
Which one does not cause deep vein Thrombosis - 
Select and explain. 
A. Oestrogen, B. Thrombocytosis, C. Paroxysmal nocturnal haemoglobinuria, D. Sickle cell anemia
D: Sickle cell anemia
Answer: D: Sickle cell anemia 
Explanation: Sickle cell anemia does not cause DVT. They cause vaso-occlusive crisis by plugging the microcirculation (aggregate of Sickle cell are formed in the capillaries because of hypoxia).