Final answer:
Set C, which includes the points (3, 7), (-7, -3), (-3, 7), (7, -3), does NOT represent a function.
Step-by-step explanation:
A set of points represents a function if each x-value is paired with one and only one y-value. Based on the given sets of points, we can determine that set C does NOT represent a function.
Set C: (3, 7), (-7, -3), (-3, 7), (7, -3)
In set C, both the x-value -3 and the x-value 7 are paired with multiple y-values. For -3, it is paired with both 7 and -3, and for 7, it is paired with both -3 and 7. This violates the definition of a function.