Kai is conducting a study about the percentage of students with jobs. His school has 2500 students. He asks everyone in his drama class to participate in a survey. He bases his findings on these results. Is this a valid study? Why or why not?
A) YES, he asked everyone in his class.
B) YES, since drama students tend to have after-school jobs.
C) NO, he should have taken a small sample from the drama class.
D) NO, the drama class does not represent all students in the school.