Question

Which relations are functions?

Choose all answers that are correct.
(Points : 5)
{(–7, 3), (–3, 1), (4, 3), (5, –2)}
{(–5, 8), (–5, –8), (3, 4), (7, 0)}
{(–1, 9), (0, 9), (9, –3), (10, 10)}
{(4, –6), (6, 0), (6, 2), (11, 20)}