According to the Centers for Disease Control and Prevention, the proportion of U. S. adults age 25 or older who smoke is .22. A researcher suspects that the rate is lower among U. S. adults 25 or older who have a bachelor's degree or higher education level. What is the null hypothesis in this case?

a. The proportion of smokers among U. S. adults 25 or older who have a bachelor's degree or higher is less than 0.22.
b. The proportion of smokers among U. S. adults 25 or older who have a bachelor's degree or higher is 0.22.
c. The proportion of smokers among U. S. adults 25 or older who have a bachelor's degree or higher is not 0.22.
d. There is no relationship between education level and smoking habits.