(04.01 LC) Which set of ordered pairs represents a function? (1 point)

a
{(0, 1), (1, 2), (2, 3), (3, 3)}

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

c
{(0, 0), (1, 2), (2, 4), (2, 6)}

d
{(0, 0), (0, 1), (2, 0), (2, 4)}