the psychology department of a school conducted a study on 20 rendom students in a third grade class of 58 students, 20 of the students were then offered a supplement., The study found that 15 of these students did better in their end-term exams compared to those who did not take the supplements . Which of the following statements can best be concluded from the above study? A Students who take supplements do better on exams. B) Students who do not take supplements do not do well on their exams. C)Supplements improve students performance in their exams. D)No conclusion can be drawn about the cause- and-effect relationship between test taking and supplement taking.