Answer:
rotation 90° CW about the origin we defined
Explanation:
The image has the same orientation (clockwise order of vertices) as the pre-image, so an even number of reflections is involved. These cannot be reflections across the x- or y-axes. The longest edge has an east-west orientation in the pre-image and a south-north orientation in the image. Any reflections must have a net effect of a rotation 90° CW.
Equivalently, the image is rotated 90° clockwise from the pre-image.
With a suitable choice of center of rotation, the image can be obtained with a single 90° CW rotation transformation.
If we define the lower left corner of the pre-image as having coordinates (-1, 2), then a 90° CW rotation about (0, 0) will yield the image.