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
Dean's shoe leather survey Comes under: 
Select and explain. 
A. Demonstration phase., B. Clinical discovery phase., C. Epidemiological phase., D. Clinical trial phase.
C: Epidemiological phase.
Answer: C: Epidemiological phase. 
Explanation: The history of community water fluoridation is categorized into four separate periods or phases.