This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pathology
What is the actual intention of doing sentinel surveillance? 
Select and explain. 
A. To know the total number of cases, B. For health planning, C. To know the natural history of the disease, D. To prevent the disease
A: To know the total number of cases
Answer: A: To know the total number of cases 
Explanation: Sentinel surveillance A method for identifying the missing cases and thereby supplementing the notified case is required Sentinel surveillance is extrapolated to the entire population to estimate the disease prevalence in the total population(Refer: K. Park's Textbook of Preventive and Social Medicine, 24th edition, pg no: 45)