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
Venous thrombosis In patients with paroxysmal nocturnal hemoglobinuria is observed in 
Select and explain. 
A. Cerebral veins, B. Leg veins, C. Intrabdominal veins, D. Axillary vein
C: Intrabdominal veins
Answer: C: Intrabdominal veins 
Explanation: Answer- C. Intrabdominal veinsVenous thrombosis is an inconstant but severe clinical manifestation of P.N.H.Thrombosis occcurs due to absence of CD59 which k a membrane attached proteinThrombosis usually occurs in abdominal veins. Intra-abdominal yeins are the most common site of thromosis in P.N.H.