Refer to the Following Paragraph to Answer the Questions Below

Refer to the following paragraph to answer the questions below.
Mary Rodale studied discrimination against women plumbers. Her hypothesis was that the greatest discrimination would be by businesses owned by men and individuals who believe strongly in traditional sex roles. She contacted 75 small business owners and 100 individual homeowners who planned to hire a plumber. She offered each subject six possible plumbers to chose from. The plumbers had varying levels of experience, training, and charged different rates. One of the six was a woman and the other five were men. She discovered that 80 percent of the male business owners chose a man plumber although a woman plumber had more experience and training and charged less for the same service. For female business owners 30 percent chose a man plumber over a better-qualified and cheaper woman. Every single homeowner who believed strongly in traditional sex role chose a male. All those who believed in nontraditional sex roles ignored gender and chose on the basis of skill and price alone.
-What is the null hypothesis for the study?

A) Women do not discriminate against women plumbers, but men do.
B) Discrimination is bad and should not occur.
C) Male small-business owners and traditionalist homeowners are more likely to discriminate against women who are plumbers.
D) There is no discrimination by small-business owners or homeowners against women plumbers.
E) none of the above