A function is either one-to-one or many-to-one function but not one-to-many. This means if a set of ordered pair has one x-coordinate with different y-coordinate, then it is not a function. Let's take a look at the choices.
1. {(3,5), (-17,-5), (3,-5), (-17,5)}
This is not a function because the x-coordinates 3 has two y-coordinates 5 and -5.
2. {(-6,-1), (13,8), (1,6), (1,-10)}
This is not a function because the x-coordinate 1 has two y-coordinates 6 and -10.
3. {(10,5), (10,-5), (5,10), (5,-10)}
This is not a function too because the x-coordinate 10 has two y-coordinates 5 and -5. In addition, the x-coordinate 5 has two y-coordinates 10 and -10.
4. ((10,5), (-10,-5), (5,10), (-5,-10)}
This is a function because there is no x-coordinate that has multiple y-coordinates. Each x-coordinates is paired to just one y-coordinate.