Which set is a function?


A)
{(0,3), (3,0), (0,4), (4,0)}


B)
{(0,2), (2,0), (4,6), (6,4)}


C)
{(2,6), (3,6), (4,6), (2,0)}


D)
{(6,2), (2,0), (4,6), (6,4)}

D)