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': 'White leg is due to - \nSelect and explain. \nA. Femoral vein thrombosis and lymphatic obstruction, B. Deep femoral vein thrombosis, C. Lymphatic obstruction only, D. None of the above', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Deep femoral vein thrombosis", 'role': 'assistant'}]