Which of the following relations is not a function?

{(0, 0), (1, 0), (2, 0)}
{(-1, 3), (4, 2), (-1, 5)}
{(1, 2), (3, -5), (-1, 7)}
{(7, -1), (3, -2), (5, -2)}

which of the following sequences represents an arithmetic sequence?

-7, -4, 1, 4,
2, -4, 8, -16,
1, 4, 9, 16,
-5, -3, -1, 1,