the preimage WXYZ is to undergo a rotation of 90° in the clockwise direction.
A 90° clockwise rotation leads to the following change in the coordinates;
(x,y) -> after rotation (y,-x)
this rule applies for all the vertices in the preimage
W - (3,-5) --> W' (-5,-3)
X - (1,-3) ---> X' (-3,-1)
Y - (-1,-5)---> Y' (-5,1)
Z - (1,-7) ---> Z' (-7,-1)
therefore the new coordinates are W' (-5,-3), X' (-3,-1), Y' (-5,1) and Z' (-7,-1)