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: Surgery
[{'content': 'Exsanguination is one of the first steps before application of a tourniquet preoperatively. All the following are contra indications for exsanguination except \nSelect and explain. \nA. Deep vein thrombosis, B. Underlying fracture, C. Presence of infection, D. Tumour', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Presence of underlying infection or tumor is an absolute contra indication for exsanguination since that can cause dissemination. Fatal pulmonary embolism may result if exsanguination is done over underlying deep vein thrombosis', 'role': 'assistant'}]