We have x = 4 repeating itself
If we graph the two points (4,1) and (4,20), then we see the relation fails the vertical line test.
The input x = 4 leads to more than one output y = 1 and y = 20 simultaneously.
This is why we don't have a function.
I think it is BD but I’m not 100% sure
..........The answer is D
N = 7 is the answerHope this helps