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
Infrabony pocket results from 
Select and explain. 
A. Trauma from occlusion, B. Dental plaque, C. Actinomyces viscosus, D. Improper tooth brushing
A: Trauma from occlusion
Answer: A: Trauma from occlusion 
Explanation: None