Shoshanna surveys 100 students attending Skinner High to find out the level of school spirit among the student body. To make sure that the 100 students Shoshanna chooses to complete her survey reflect the general characteristics and attitudes of the entire student body at Skinner High, Shoshanna should use which of the following?
A. random assignment
B. random sample (selection)
c. within-subject design
d. double blind study
e. single blind study