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 first bone to ossify in body is: \nSelect and explain. \nA. Lower end of femur, B. Clavicle, C. Upper end of humerus, D. Upper end of tibia', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Clavicle', 'role': 'assistant'}]