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
What is false about case fatality rate? 
Select and explain. 
A. It is a ratio, B. It is not useful for acute disease, C. Related to virulence, D. Not useful in chronic diseases
B: It is not useful for acute disease
Answer: B: It is not useful for acute disease 
Explanation: Case fatality rate represents the killing power of the disease. It's simply the ratio of deaths to diseases. Ref: 25th edition, Park's Textbook of Preventive and Social Medicine, Page no. 66