Answer:
To find the image of point D after the translation (x,y) --> (x + 13.5, y - 8.5), we need to add 13.5 to the x-coordinate of D and subtract 8.5 from the y-coordinate of D.
Therefore, the image of point D after the translation is:
D' = (32.5 + 13.5, -23 - 8.5)
= (46, -31.5)
So the answer is D. (46, -31.5).