Which set of ordered pairs (x, y) could represent a linear function?
A = {(-5, -1), (2,2), (4,3), (6,4)}
B = {(-6, -2), (-3,1), (0,3), (3,6)}
C = {(1,7), (3, 6), (5,5), (7,4)}
D = {(-2,4), (-1,2), (1,-2), (2, -6)}