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
Average Diameter of Apical foramen in an 18-25 years old adult is 
Select and explain. 
A. 400 micrometer, B. 502 micrometer, C. 681 micrometer, D. 602 micrometer
B: 502 micrometer
Answer: B: 502 micrometer 
Explanation: None