Describe fully the single transformation which takes shape A to shape B

The single transformation that maps shape A onto shape B is a reflection across the line y = 2
Step-by-step explanation:
The coordinates of the A are A(-1, 3)
The coordinates of the corresponding point on B is (-1, 1)
Therefore, given that the x-coordinates of the pre-image A and the image B are the same, therefore, we have that image B is a reflection of image A
Also half the vertical distance between figure A and B = (3 - 1)/2 = 1
Therefore, figure A is obtained from figure B by reflection across a horizontal line, 1 unit below the lowest y-coordinate of figure A which is the line y = 3 - 1 = 2
Therefore, we have;
The single transformation that maps shape A onto shape B is a reflection across the line y = 2