Answer: B. 1/6
Step-by-step explanation:
To find the scale factor from triangle ABC to triangle DEF, you can divide each side length by its corresponding side on the other triangle.
72 ÷ 12 = 6
42 ÷ 7 = 6
66 ÷ 11 = 6
Now, the options are narrowed down to either B or C. Since the dilation shown reduces the size of triangle ABC to triangle DEF, it is a reduction. Therefore, the scale factor must be a fraction, leaving the only correct answer to be choice B.
I hope this helps!