Answer:
Option C.
Explanation:
Given information: WX=8m and W'X'=6m
It is given that Trapezoid W′X′Y′Z′ is the image of trapezoid WXYZ under a dilation through point C.
Scale factor is the ratio of corresponding sides of image and preimage.

For the given figure,



Since image and preimage lie on the same side of the center of dilation. So, the scale factor is positive number.
Therefore, the correct option is C.