whenever you are trying to determine whether a graph determines a function or not, just draw a vertically straight line through the graph's line. If you draw that line and it goes through the graph's line more than once, then the graph does not represent a function.
The answer is C however I always felt the “vertical line test” was for people who can’t do math and need images. A function is any equation that does not have same out come with different numbers I.E x^2 is not a function.
