Select Is a Function or Is not a Function to correctly classify each relation.
is a function or not a function

{(2, 2),(4, 4),(6, 6),(8, 8)}

{(0, 3),(3, 5),(5, 6),(8, 4)

{(1, 2),(3, 3),(4, 8),(6, 3)}

{(3, 4),(5, 2),(5, 6),(7, 3)}