The Average Number of Hours for a Random Sample of Mail

The average number of hours for a random sample of mail order pharmacists from company A was 50.1 hours last year. It is believed that changes to medical insurance have led to a reduction in the average work week. To test the validity of this belief, the hypotheses are

A) H₀: U > 50.1, H_{a : U < 50.1.}
B) H₀: U = 50.1, H_{a : U ≠ 50.1.}
C) ​H₀: U ≤ 50.1, H_{a : U > 50.1.}
D) H₀: U ≥ 50.1, H_{a : U < 50.1.}