Four digits, 6159, are painted on a door in straight strokes. A dashed mirror stands to their right. Which panel shows their mirror image?

In the mirror the digits come in the order 9 5 1 6 and each is reversed: the 9 opens to the right, the 5 looks like a 2, the 1 has its flag on the right and the 6 faces left: (b). (c) forgets to reverse the 1; (a) is the image in water and (d) is a half-turn.