ANSWER
D. 3
EXPLANATION
We want to find the scale factor applied from figure A to figure B.
To do that, we have to divide any of the side lengths of figure B by a corresponding side length of figure A.
Let us divide the side length of the left sides of both figures.
Therefore, the scale factor is:
[tex]\begin{gathered} SF=\frac{18}{6} \\ SF=3 \end{gathered}[/tex]
That is the scale factor.
