To infer the political tendencies of the students at your college/university, you sample 150 of them. Only one of the following is a simple random sample: You
a) make sure that the proportion of minorities are the same in your sample as in the entire student body.
b) have your statistical package generate 150 random numbers in the range from 1 to the total number of students in your academic institution, and then choose the corresponding names in the student telephone directory.
c) go to the main dining hall on campus and interview students randomly there.
d) call every fiftieth person in the student directory at 9 a.m. If the person does not answer the phone, you pick the next name listed, and so on.