A $3\times 3$ tile lies just above a mirror placed flat on the floor (dashed line). Which panel shows the tile's image in this mirror?

A flat mirror below acts like water: the top row and bottom row swap, the columns stay. The blue square moves to the bottom-left, the yellow square stays in the middle row on the right, the dot goes to the bottom-right cell and the orange corner triangle goes to the top-middle cell with its corner now at the bottom-left: (d). (a) swaps the columns, (b) does both and (c) is a quarter-turn.