This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
Which one of the following is a coho study 
Select and explain. 
A. Noh Karelia project, B. Standard three community study, C. MRFIT study, D. Framingham hea study
D: Framingham hea study
Answer: D: Framingham hea study 
Explanation: A coho study is a paicular form of a longitudinal study that samples a coho (a group of people who share a defining characteristic, typically those who experienced a common event in a selected period, such as bih or graduation), performing a cross-section at intervals through time. Ref: 25th edition, Park's Textbook of Preventive and Social Medicine, Page no. 83