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
Framingham Heart Study is an example of : 
Select and explain. 
A. Case control study, B. Cohort study, C. Cross-sectional study, D. Interventional study
B: Cohort study
Answer: B: Cohort study 
Explanation: FRAMINGHAM HEART STUDY:

Is a classical example of cohort study
Initiated in 1948 by US Public Health Service at Framingham, a town in Massachusetts, USA

Aim: To study the relationship of risk factors (serum cholesterol, blood pressure, weight,smoking) to the subsequent development of cardiovascular diseases.