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 pathological fracture is \nSelect and explain. \nA. Delayed union, B. Mal union, C. Non union, D. Secondary deposits', 'role': 'user'}, {'content': 'Answer: D \nExplanation: D i.e. Secondary deposits', 'role': 'assistant'}]