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
[{'content': 'Denominator while calculating the secondary attack rate includes - \nSelect and explain. \nA. All the people living in next fifty houses, B. All the close contacts, C. All susceptible amongst close contact, D. All susceptible in the whole village', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. is \'c\' i.e., All susceptible amongst close contact Secondary attack rate (SAR) SAR is defined as "the number of exposed persons developing the disease within the range of incubation period, following exposure to primary case".', 'role': 'assistant'}]