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
Kirkland knife is used for: 
Select and explain. 
A. External bevel incision, B. Internal bevel incision, C. Horizontal incision, D. All of the above
A: External bevel incision
Answer: A: External bevel incision 
Explanation: None