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
If annual growth rate of a population is 1.5-2%, what number ofyears will be required to double the population? 
Select and explain. 
A. 70-47 years, B. 47-35 years, C. 35-28 years, D. 28-23
B: 47-35 years
Answer: B: 47-35 years 
Explanation: Ans. is 'b' i.e. 47-35 years