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
H-file is used to 
Select and explain. 
A. Locate the canal orifice, B. Flare the root canal, C. For irrigation of root canal, D. All of the above
B: Flare the root canal
Answer: B: Flare the root canal 
Explanation: None