Hello!
If this figure was reflected diagonally, it would not match up with our final figure. Therefore, A is not our answer.
A 90 degree rotation would not put our figure across the graph, so our answer is not B or C.
A 180 degree rotation will put our figure in Quadrant 4 and will match up with our final figure.
Therefore, our answer is C) 180° rotation about the origin
I hope this helps!