This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
[{'content': 'Indicators of osteoblastic activity - \nSelect and explain. \nA. Alkaline phosphatase, B. Osteocalcin, C. Hydroxyproline, D. Acid phosphatase', 'role': 'user'}, {'content': 'Answer: A \nExplanation: bone formation indicator is alkaline phosphatase ( Harrison 17 pg 2382)', 'role': 'assistant'}]