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
[{'content': 'All of the following are causes of Deep venous thrombosis, EXCEPT: \nSelect and explain. \nA. Diabetes Mellitus, B. Prolonged surgery, C. Oral contraceptives, D. Paroxysmal Nocturnal Hemoglobinuria (PNH)', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Conditions which lead to stasis, vascular injury, and hypercoagulability (Virchows triad) act as risk factors for DVT. Acquired risk factors include older age, cancer, surgery, trauma, immobilization, hormone replacement therapy, oral contraceptive use, pregnancy, neurologic disease, cardiac disease, and antiphospholipid antibodies. Hematologic disorders associated with DVT include disseminated intravascular coagulation, heparin-induced thrombocytopenia, antiphospholipid antibody syndrome, TTP, HUS, polycythemia vera, PNH and essential thrombocythemia. Inflammatory bowel disease, systemic lupus erythematosus, and obesity are additionally associated with DVT. Ref: Current Diagnosis and Treatment: Surgery, 13th Edition, Chapter 35', 'role': 'assistant'}]