Which of the following shows why rectangle wxyz is congruent to rectangle w'x'y'z'?

a. the rectangle was rotated 180° clockwise about the origin and shifted 3 units in the x direction.
b. the rectangle was rotated 90° clockwise about the origin and shifted 3 units in the x direction.
c. the rectangle was rotated 180° clockwise about the origin and shifted 3 units in the y direction.
d. the rectangle was rotated 90° clockwise about the origin and shifted 3 units in the y direction.