The administration at a local high school is considering building a new gym. In order to find out how the student body feels about this, a student organization decides to conduct a survey of the students. Which of the sampling methods in A–D should be unbiased?
A. Survey random students who are leaving after school sports practices.

B. Survey random students who are going to watch a basketball game at the high school.

C. Obtain a list of all seniors, randomly select students from the list, and survey the students selected.

D. Obtain a list of all students attending the high school, randomly select students from the list, and survey the students selected.