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: Anatomy
[{'content': 'The ossification center of pisiform bone appears at the age of - \nSelect and explain. \nA. 10-11 years, B. 12-13 years, C. 14-15 years, D. 15-16 years', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]