Point A shows that she is incorrect.
With functions, you can perform the "straight line test through each point. If the line goes through both points, you know it's not a function.
If we plotted point A, it'd fail the straight line test because the given point (-6, 7) already has -6 as an x value.
Hope this helps!
All real numbers that are less that -3 or greater than or equal to 5 is x <-3 and x>=5