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)}
A
B
C
D