Answer:
its d because who askes that question
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.
It's a, you can just do the vertical line test where if you put a line on that graph and it hits two or more points then it isn't a function but if it only hits 1 then it is
