A powerful women's group has claimed that men and women differ in attitudes about sexual discrimination. A group of 50 men (group 1) and 40 women (group 2) were asked if they thought sexual discrimination is a problem in the United States. Of those sampled, 11 of the men and 19 of the women did believe that sexual discrimination is a problem. Assuming W designates women's responses and M designates men's, which of the following are the appropriate null and alternative hypotheses to test the group's claim?

a) H0: πM - πW  ≤ 0 versus H1: πM - πW > 0

b) H0: πM - πW  ≥ 0 versus H1: πM- πW < 0

c) H0: πM - πW  = 0 versus H1: πM - πW ≠ 0

d) H0: πM - πW  ≠ 0 versus H1: πM - πW = 0