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: Pathology
[{'content': 'Osteoblasts produce - \nSelect and explain. \nA. Collagen, B. Calcium, C. Pyrophosphate, D. Monosodium urate', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Osteoblast-Derived Proteins\nType 1 collagen\nCell adhesion proteins\xa0\n\xa0 \xa0 \xa0osteopontin, fibronectin, thrombospondin\nCalcium-binding proteins\n\xa0 \xa0 \xa0Osteonectin, bone sialoprotein\nProteins involved in mineralization\n\xa0 \xa0 Osteocalcin\xa0\nEnzymes\n\xa0 \xa0 Collagenase, alkaline phosphatase\nGrowth factors\n\xa0 \xa0IGF-1, TGF-β, PDGF\nCytokines\n\xa0 \xa0Prostaglandins, IL-1, IL-6, RANKL\nProteins Concentrated from Serum\nβ2-microglobulin\nAlbumin', 'role': 'assistant'}]