Sets: Given A = { 4, 5, 6, 8} and B = {8, 6, 5} Relations R, S, and T from set A to set B are defined by R = {(4,8), (4, 6), (4, 5) S = {(4, 8), (5,8), (6, 8), (8, 8)} T= {(5,5), (6, 6), (8,8)} Which of these relations are also functions? (Choose all that apply) S is a function Ris a function Tis a function