An administrator wants to know what proportion of the 80,000 teachers in their state have a Master's degree. Thet take an SRS of 100 teachers from a statewide database with every teacher, and they find 55 teachers in the sample have a Master's degree.

Which of the following is a 99% confidence interval for the proportion of teachers in the state with a Master's degree?

a. 0.55 ± 0.128
b. 0.55 ± 0.098
c. 55 ± 0.128.
d. 55 ± 0.098