Answer: "A"
Step-by-step explanation: To determine which relation is a function, we use the vertical line test. In other words, if we can draw a line that passes through only one point, then the relation is a function.
Image provided.
In the picture, you can see vertical lines and notice that the lines have only one point on them. On the other graphs, there is more than one point on the same line which makes it not a function.
