Answer:
The last one: {(-2,-2), (0,0), (-4,-4), (0,-2)}
Explanation:
In a function, the x value should not repeat.
The only option that has 2 of the same x values is the last one.
Another way to do this is the vertical line test.
Graph all points, and if two points are on the same vertical line, it's not a function. If all points are on different vertical lines, it is a function.
Hope this helps you understand! :D