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
An important measure of the communicability of a disease is - 
Select and explain. 
A. Case fatality rate, B. Disease specific mortality rate, C. Infection rate, D. Secondary attack rate
D: Secondary attack rate
Answer: D: Secondary attack rate 
Explanation: None