The proportion of junior executives leaving large manufacturing companies within three years is to be estimated within 2 percent. The 0.95 degree of confidence is to be used. A study conducted several years ago revealed that the percent of junior executives leaving within three years was 25. To update this study, the files of how many junior executives should be studied?
a. 1,276
b. 3,120
c. 1,657
d. 1,801