#### Answer

not a function

#### Work Step by Step

$\bf{\text{Solution Outline:}}$
Express first the given diagram as a set of ordered pairs. Then check if the first components of the ordered pairs are all unique.
$\bf{\text{Solution Details:}}$
In terms of a set of ordered pairs, the relation in the given diagram is equivalent to
\begin{array}{l}\require{cancel}
R=\{ (-3,4),(-3,1),(2,0) \}
.\end{array}
Since the first component, $-3,$ is used more than once, then the given relation is not a function.