Question

which transformation shows a reflection of △def?

Explanation:

Step1: Recall reflection properties

In a reflection, corresponding points are equidistant from the line of reflection and the figure is flipped over the line of reflection. The first - shown transformation has the correct orientation and distance - relationship of corresponding points of $\triangle DEF$ and $\triangle D'E'F'$ for a reflection.

Answer:

The first transformation shown.