A researcher is funded to obtain an estimate for the population proportion of smokers who have tried using e-cigarettes. She plans to interview 100 smokers and report a 95% confidence interval. Previous studies have estimated that 20% of smokers have tried e-cigarettes.

What do you recommend to achieve the smallest margin of error?

A.Plan to interview90smokers

B.Use a 90% confidence interval

C.Use analysis of variance

D.Use a 99% confidence interval