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': 'which collagen can be Immuno localized in PDL and gingiva: \nSelect and explain. \nA. Type 1 collagen, B. Type 3 collagen, C. Type 4 collagen, D. Type 6 collagen', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]