Answer
$G$
Work Step by Step
Graph $G$ is a function because there is exactly one value of $y$ corresponding to each value of $x$.
The other graphs are not functions because all of them have more than one value of $y$ for certain values of $x$; therefore, the other graphs do not pass the vertical line test where if we draw a vertical line through certain points in the graphs, there will be more than one value in the range for certain values in the domain.
