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: Dental
[{'content': 'Following are the mature mineralized matrix marker of the periodontal ligament except: \nSelect and explain. \nA. Type 1 and type 3 collagen., B. Osteonectin., C. Alkaline phosphate., D. Osteopontin.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Markers for Periodontal Ligament Stem Cells\n1. Bone Marrow Markers\n\nSTRO-1\n\n2. Perivascular Cell Markers\n\nCD146\nαSMA\nPericyte associated antigen 3G5\nCD106\n\n3. Mature Mineralized Matrix Markers\n\nAlkaline phosphatase\nOsteonectin\nOsteopontin\nOsteocalcin\nBone sialoproteins\n\n4. Connective Tissue Protein Markers\n\nType I and III collagen', 'role': 'assistant'}]