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
All of the following features are true about cross sectional study except- 
Select and explain. 
A. All cases are seen at one point in time, B. Follow up is not a necessary feature, C. More useful for chronic disease, D. Cause and effect relationship can be established
D: Cause and effect relationship can be established
Answer: D: Cause and effect relationship can be established 
Explanation: Although a cross-sectional study provides information about disease prevalence it provide very little information of about the natural history of the disease or about the rate of occurrence of the disease (refer pg no:69 park 23 rd edition)