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: Social & Preventive Medicine
True about case control study - 
Select and explain. 
A. Less expensive, B. Those with disease and not diseased compared, C. Attributable risk is estimated, D. None of these
A: Less expensive
Answer: A: Less expensive 
Explanation: Ans. is 'a' i.e., Less expensive