Students Who Study Statistics in College Tend to Score Higher

Multiple Choice

Students who study statistics in college tend to score higher on the Graduate Record Examinations (GRE) math section than students who do not study statistics. Which is true?

A) This shows that studying statistics improves your knowledge for the GRE.
B) Students who choose to study statistics are probably already good at math, so we can't conclude anything about cause-and-effect.
C) This makes no sense because you can't compute the correlation between studying statistics and GRE math section test scores.
D) There is a positive correlation between whether or not a student studied statistics and the student's GRE math section test score.