In a large lecture class, the professor announced that the range of scores on a recent exam was normally distributed between 51 and 87. Using the Empirical Rule to estimate s, how many students would you need to sample to estimate the true mean score for the class with 90 percent confidence and an error of ± 2?
A. About 17 students
B. About 35 students
C. About 188 students
D. About 25 students