A researcher wants to collect data about the study habits of sophomores at Harmond University. From the sophomore class of 2,300 students, she wants to collect a sample of 70 students. Which of the following sampling methods will yield the most representative sample?
A. Assigning each sophomore a number and then randomly generating 70 numbers from that list.
B. Randomly selecting 70 sophomores entering the university's main library on a randomly selected evening.
C. Selecting the 70 sophomores whose grade point averages (GPA) fall closest to the mean GPA of the sophomore class.
D. Randomly selecting 70 sophomores who are members of college fraternities.