The answer is A. This can be seen in the table where y can be both 4 and 3 for when x = 3. In a function, an output can have more than one input, but an input can have have only one output.
Answer: A function is so F(X) = Y where for every X exist only one Y, in this case you can see that F(3) = 4 and F(3) = 3, so the independent variable x = 3, has two solutions y.
So the solution is A, because a function cannot have two different y values for one x value.
