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
The failure of a calcium hydroxide pulpotomy done on a
primary 1st molar is due to: 
Select and explain. 
A. Internal resorption, B. External resorption, C. Pulp calcification, D. Pulp fibrosis
A: Internal resorption
Answer: A: Internal resorption 
Explanation: None