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
Secondary attack rate (SAR) denominator includes 
Select and explain. 
A. Population, B. Primary case, C. Exposed susceptible contacts, D. Person developing symptoms
C: Exposed susceptible contacts
Answer: C: Exposed susceptible contacts 
Explanation: None