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': 'Z-plasty ideal angle is: \nSelect and explain. \nA. 30 degrees, B. 45 degrees, C. 60 degrees, D. 90 degrees', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]