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
Which one of the following is a good index of the severity of an acute disease? 
Select and explain. 
A. Case fatality rate, B. Cause specific death rate, C. Standardized mortality ratio, D. Five year survival
A: Case fatality rate
Answer: A: Case fatality rate 
Explanation: Case fatality rate measures the killing power of a disease, for acute infectious diseases like food poisoning, cholera, measles.
It is simply the ratio (it is not  a RATE) of deaths to cases.