This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S, 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: *predisposing systemic causes for cerebral venous thrombosis: dehyration,pregnancy,Behcet's disease ,thrombophilia,hypotension,oral contraceptive use. *Local causes are:paranasal sinusitis,meningitis,subdural empyema,facial skin infection,otitis media,mastoiditis,skull fracture,penetrating head and eye wounds. Ref Harrison20th edition pg 2345