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': 'How much length is increased in Z plasty when it is done at 60 degrees? \nSelect and explain. \nA. 25%, B. 50%, C. 75%, D. 100%', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]