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': 'The most common cause of non union is \nSelect and explain. \nA. Infection, B. Inadequate immobilization, C. Ischaemia, D. Soft tissue interposition', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Inadequate immobilization', 'role': 'assistant'}]