Question 8 (1 point) Saved Researchers conducted a study to determine whether taking a multivitamin daily affects the energy level of college students in the U.S. To perform their study, researchers took a sample of 1500 college students from the five largest universities in the U.S. Half of the sample took a multivitamin daily and the other half took a placebo daily. What are the variables in this study? Daily multivitamins and 1500 college students Multivitamin and Placebo Daily vitamin and energy level College students and daily multivitamin Energy level and 1500 college students O Hi m P 9 77'F Clear