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
Avulsed tooth dip into the citric acid because 
Select and explain. 
A. To remove periodontal ligament, B. To increase the surface area, C. To provide a barrier, D. To increase tension
A: To remove periodontal ligament
Answer: A: To remove periodontal ligament 
Explanation: None