A university wants to conduct a sample survey to determine the average number of students who earned a GPA higher than 3.5. Which of the following survey methods is most likely to produce valid results?


A. The university surveys students who earned less than a 3.5 GPA.
B. The university surveys every other student who earned more than a 3.5 GPA.
C. The university surveys 600 randomly selected students who attend the university.
D. The university selects one department and surveys all of its students