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
Calculate the prevalence if incidence is 2 cases per 1,000 population per year and mean duration is 4 years- 
Select and explain. 
A. 8 mases per 1,000 population, B. 2 cases per 1,000 population, C. 0.5 cases per 1,000 population, D. 32 cases per 1,000 population
A: 8 mases per 1,000 population
Answer: A: 8 mases per 1,000 population 
Explanation: prevalence is calculated as the product of incidence and mean duration of a disease in a community.during a specific period,here it is given as 4 *2 cases per 1000 population. ref:park&;s textbook,ed 22,pg no 67