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
Best indicator of availability,utilisation & effectiveness of health services- 
Select and explain. 
A. IMR, B. MMR, C. Hospital bed OCR, D. DALY
A: IMR
Answer: A: IMR 
Explanation: Ans. is 'a' i.e., IMR