This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other Key Definitions & Concepts, Subject name: Social & Preventive Medicine
Expectation of life, free of disability is known as:- 
Select and explain. 
A. Park's index, B. Smith's index, C. Sullivan index, D. Life index
C: Sullivan index
Answer: C: Sullivan index 
Explanation: Sullivan's index is defined as Disability free life expectancy (DFLE). Sullivan's index = Life expectancy -- duration of disability.