Which of the following sets of coordinate pairs is not a relationship where y is a function of x?

1){(-3,1),(0,5), (2,7), (5, 1)}

2) {(2,4),(-1,0), (1,7),(-2,-4)}

3){(-3, 10),(-2,5), (1, 2), (2,5)}

4){(4,16), (5, 25), (7,49), (10,100)}

please help ;)