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': 'Delayed union of fracture of a bone follo-wing a surgical treatment may be due to \nSelect and explain. \nA. Infection, B. Inadequate circulation, C. Inadequate mobilization, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: D i.e. All', 'role': 'assistant'}]