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
Incidence rate of lung cancer among smokers is 8 per 1000 and among non smokers is 1 per 1000. Population attibutable risk is - 
Select and explain. 
A. 89%, B. 95%, C. 10%, D. 100%
A: 89%
Answer: A: 89% 
Explanation: It is the incidence of the disease in the total population minus the incidence of disease among those who were not exposed to the suspected causal factor. The concept of population attributable risk is useful in that it provides an estimate of the amount by which the disease could be eliminated or modified (refer pgno:79 park 23 rd edition)