This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other Analytical Studies, Subject name: Social & Preventive Medicine
Which of the following is false about Longitudinal studies? 
Select and explain. 
A. Helps us study natural history of a disease, B. Helps in identification of risk factor of a disease, C. Helps us find out rate of occurrence of new cases of a disease, D. Easy to organize and less time consuming
D: Easy to organize and less time consuming
Answer: D: Easy to organize and less time consuming 
Explanation: Longitudinal studies Longitudinal studies are defined as studies having a direction. Longitudinal studies : Helps us study natural history of a disease. Helps in identification of risk factors of a disease. Helps in find out rate of occurrence of new cases of a diseases. Difficult to organize and more time consuming. Includes 1. Coho study :Forward (prospective) direction; 2 . Case control study :Backward (retrospective) direction. Veical study/ Non-longitudinal study : Include cross-sectional study aka snapshot/ prevalence study , Ecological study aka co-relational study.