Which set of ordered pairs is a function?
{(-6,-4).(-4,-2). (0,0).(-4,2).(-6,4)}
{(-5,1).(-3,2).(-1,3). (1,4). (3,5)}
{(-2,1), (-4, 2), (0, 3), (4.1). (-2,5)}
{(-1,5). (-1,4),(-1,3), (-1,2), (-1, 1)}