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 name of the sample group of individuals when followed for successive examination to evaluate the effect of oral preventive programmes is: 
Select and explain. 
A. Panel group, B. Cohort group, C. High risk group, D. Prospective group
A: Panel group
Answer: A: Panel group 
Explanation: None