Which of the following tables represents a relation that is a function?

x y
−5 −3
−2 3
−1 1
3 4
3 −1

x y
−5 4
−2 4
0 −4
0 4
3 4

x y
−4 0
−2 2
0 3
2 0
3 4

x y
1 −4
1 −2
1 0
1 2
1 4

The first table represents a relation that is a function because each input value (x) is associated with only one output value (y).