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
Thermafil is 
Select and explain. 
A. An endodontic obturater, B. An enlarging instrument, C. An instrument to remove pulp, D. Is a cold gutta percha technique
A: An endodontic obturater
Answer: A: An endodontic obturater 
Explanation: None