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
Communicability is best measured by 
Select and explain. 
A. Serial Interval, B. Secondary attack rate, C. Case fatality rate, D. Generation time
B: Secondary attack rate
Answer: B: Secondary attack rate 
Explanation: SAR is defined as the number of exposed persons developing the disease within the range of the incubation period, following exposure to the primary case. Hence it shows the communicability.