This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolic Disorders Leading to Osteosclerosis, Subject name: Orthopaedics
[{'content': 'Marker for bone formation is: \nSelect and explain. \nA. Tartrate resistant acid phosphate, B. Osteocalcin, C. Urinary calcium, D. Serum nucleotidase', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. is \'b\' ie Osteocalcin "Osteoblasts are bone forming cells that synthesize the collagenous component of the osteoid matrix. They also initial the process of bone mineralization though the elaboration of osteocalcin and calcium binding proteins (osteonectin and bone sialo protein) required for the deposition of inorganic hydroxyapatite in the organic osteoid that they produce. Osteocalcin is a product of osteoblast uniquely and is measurable in the serum. Thus it is a sensitive and specific marker of osteoblastic activity."', 'role': 'assistant'}]