This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
All are true regarding case fatality rate except - 
Select and explain. 
A. Represents killing power of disease, B. Closely related to virulence, C. Very useful for chronic disease, D. May vary in different epidemic for same disease
C: Very useful for chronic disease
Answer: C: Very useful for chronic disease 
Explanation: ref: Park&;s 23rd edition pg 58 used for acute infectious diseases like food poisoning, cholera, measles.