Step-by-step explanation: Here were given 4 relations in the form of graphs and were asked to determine which one 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.
Notice that in this problem, every vertical line draw on a
graph passes through more than 1 point except for W.
So W represents a function.
