This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Occupational Health, Subject name: Social & Preventive Medicine
Of 25 persons are working on a project for 30 years. There is how many person-years of employement. 
Select and explain. 
A. 75, B. 750, C. 120, D. 1200
B: 750
Answer: B: 750 
Explanation: Ans. is 'b' i.e., 750 "10000 people working for 1 year would lead to 1000 person years of employment"* Thus, 25 persons working for 30 years will lead to 750 person-years of employment.