Answer:
C
Explanation:
A function represents the relationship between the inputs and outputs.
Vertical Line Test
The question gives us multiple representations of relationships, so we need to use different methods to evaluate each. For the graph, we can use the vertical line test. This test is when you draw vertical lines on the graph. If you can draw a vertical line anywhere on the graph and not have it intersect with more than one point, then the graph is a function.
For answer A, if you draw a vertical line at x = -1, the line intersects with 2 different points. This means that A cannot be a function.
Repeating X-Values
For all of the other answer choices, we are given some form of a table of x and y-values. In functions, x-values do not repeat. This means that for every x-value there will only be 1 y-value.
For example, answer B has 2 different y-values for x = -1; thus B cannot be a function.
Also, answer D has different y-values for x = 3, so it is also not a function.
However, every x-value in answer C is unique. Y-values repeat, but it's still a function because x-values do not. This means that C is the only function.