A researcher thinks that attitudes toward the death penalty vary by sex. What is likely to be his Null Hypothesis?

a. The population of men and the population of women have different attitudes toward the death penalty.
b. The population of men and the population of women have similar attitudes toward the death penalty.
c. The population of women favors the death penalty more than the population of men does.
d. The population of men favors the death penalty more than the population of women does