Which of the following is an example of a function?


{(3, 4), (4, 8), (6, 6), (7, 10)}


{(0, 2), (1, -4), (1, -3), (3, 6)}


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


{(5, 7), (6, 8), (6, 9), (7, 10)}