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
Type of external root resorption occur in concussion and subluxation: 
Select and explain. 
A. Surface resorption, B. Replacement resorption, C. Ankylosis resorption, D. Inflammatory root resorption
A: Surface resorption
Answer: A: Surface resorption 
Explanation: None