The relations given in options 1, 2, and 3 are not functions only Graph 4 is a function.
What is the function?
A function is an expression, or rule that defined the relation between two variables.
If we use the vertical line test.
Imagine a vertical line moving from left to right.
If in any position of the vertical line, it intersects more than one point on the graph, then it is not a function.
In graphs 1 and 2 it is clear that there are many vertical lines than would intersect the graph at more than one point.
In graph 3, a vertical line would intersect the vertical parts of the graph at more than 1 point, so graph 3 is not a function.
Learn more about function here;
https://brainly.com/question/21145944
