The code 4R7 is first seen in the dashed mirror, and then that mirror image is seen in the water below. Which panel shows what is finally seen?

The mirror swaps left and right, and the water then swaps top and bottom; together they make a half-turn $(180^{\circ }$ rotation). So the order becomes 7, R, 4, each upside down and back to front: (c). (a) is only the mirror step, (d) only the water step, and (b) leaves the R unturned.