Which function has an inverse that is also a function?
{(-1, -2), (0, 4), (1, 3), (5, 14), (7,4)}
{(-1, 2), (0, 4), (1, 5), (5, 4), (7, 2)}
{(-1, 3), (0, 4), (1, 14), (5, 6), (7, 2)}
e {(-1, 4), (0, 4), (1, 2), (5, 3), (7, 1)}