Jim works for the housing authority and wants to estimate the mean square footage of apartments for budgeting purposes, so he takes a random sample of 96 apartments. If he knows the population standard deviation of square footage of apartments, what confidence coefficient would he use if he wanted to find a confidence interval for the mean square footage of apartments using:

a.) 90 percent sign confidence level?
b.) 99 percent sign confidence level?
c.) 99.9 percent sign confidence level?
Round your answers to three decimal places.