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
The first fibers to be destroyed in periodontitis are? 
Select and explain. 
A. Free gingival, B. Oblique, C. Horizontal, D. Trans septal
A: Free gingival
Answer: A: Free gingival 
Explanation: None