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: Medicine
Sentinel surveillance is done for: September 2003 
Select and explain. 
A. Missed cases, B. Subclinical case, C. Index cases, D. Prodromal infection cases
A: Missed cases
Answer: A: Missed cases 
Explanation: Ans. A i.e. Missed cases