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
Most commonly used material post pulpectomy is: 
Select and explain. 
A. ZOE., B. Gutta-percha., C. META PEX., D. All of the above.
A: ZOE.
Answer: A: ZOE. 
Explanation: None