2) Which set of ordered pairs represents a function?
a) {(2, 3), (3, 5), (2.0), (5,3)}
b) {(4,2), (8, 2), (-3, 2), (1, 2)}
c) {(-3, 4), (-3, 2), (-3,-4), (-3, 7)}
d) {(5,8), (-4,0), (0, -3), (5,-3)}