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
which collagen can be Immuno localized in PDL and gingiva: 
Select and explain. 
A. Type 1 collagen, B. Type 3 collagen, C. Type 4 collagen, D. Type 6 collagen
D: Type 6 collagen
Answer: D: Type 6 collagen 
Explanation: None