The mean age of bus drivers in Chicago is assumed to be 50.9 years. Which of the following options represents the correct statement for the hypothesis?
A. Ho: u = 50.9; Ha: U + 50.9
B. Ho: u > 50.9; Ha: u < 50.9
C. Ho: u < 50.9; Ha: u > 50.9
D. Ho: u = 50.9; Ha: u = 50.9