Which relations are functions? Choose all answers that are correct.
{(-5, 3), (-2, 3), (-1, 8), (0, 0);
{(-6, 0), (-4, 0), (9,0), (15, 0)}
{(-10, 7), (-3, 1), (-3,0), (4, -9)}
(((
{(0, 0), (2, 2), (3, 3), (7, 7)}