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
Duration for heat pulp testing is: 
Select and explain. 
A. 5 seconds., B. 10 second, C. 15 second, D. 20 second
A: 5 seconds.
Answer: A: 5 seconds. 
Explanation: None