Answer: function
Step-by-step explanation: Here were given a relation in
the form of a graph and we're asked if it represents a function.
In this situation, we would use what is called the vertical line test.
In other words, if we can draw a vertical line that passes through more
than one point on the graph, then the relation is not a function.
In this problem, there is no way to draw a vertical
line that passes through more than one point on a graph.
Therefore, this relation must be a function.