Which of the following relations represents a function?


{ (-2, 1), (0, 5), (1, -3), (-2, 0)}

{ (-3, 1), (1, 4), (-2, 1), (0, 3)}

{(-1, 3) (-2, 3) (-1, 5) (-2, 5)}

{ (4, 2), (4, 3), (4, 5), (4, 7)}