This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Non communicable diseases, Subject name: Social & Preventive Medicine
Framingham hea study is - 
Select and explain. 
A. Case-control study, B. Coho study, C. Cross-sectional study, D. None
B: Coho study
Answer: B: Coho study 
Explanation: Park's textbook of preventive and social medicine 23rd edition. Framingham study- coho study- the study is identified prior to the appearance of the disease . It proceeds forward from cause to effect. Framingham study- has played a major role in establishing the nature of CHD risk factors and their relative impoance .