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
All are predisposing causes of cerebral venous thrombosis except - 
Select and explain. 
A. Hypotension, B. Oral contraceptives, C. Pregnancy, D. Aplastic anaemia
D: Aplastic anaemia
Answer: D: Aplastic anaemia 
Explanation: None