A new study finds that college upperclassmen (juniors and seniors) are less likely than lower classmen (freshmen and sophomores) to stop and pick up a $1 left lying on the ground by the researchers. In this study was the dependent variable and was the independent variable. O a. Likelihood of picking up the $1 bill; college level O b. Underclassmen; The $1 bill O C. College level; Likelihood of picking up the $1 bill O d. Age; Time