Answer
The graph is continuous.
Work Step by Step
Fractional pounds of walnuts makes sense, so connect the points. The graph is continuous.
$c=6w$
Let's make a list of values:
$w=0 \rightarrow c=0$
$w=1 \rightarrow c=6$
$w=2 \rightarrow c=12$
$w=3 \rightarrow c=18$