This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Pharmacology
[{'content': 'Which of the following is not used for thrombo prophylaxis \nSelect and explain. \nA. Heparin, B. Warfarin, C. Antithrombin 3, D. Aspirin', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Refer Katzung 10/e p 544 Anticoagulants are mainly used for venous thrombosis and are highly effective in treatment and prophylaxis of deep vein thrombosis Warfarin is most commonly used drug in a patient with chronic atrial fibrillation Aspirin and heparin in combination are recommended for unstable angina', 'role': 'assistant'}]