A $4\times 4$ grid has two shaded squares, a red half-square and two dots. The mirror stands on its left. Which panel shows the grid in the mirror?

Each item keeps its row but moves to the mirror column (column 1 ↔ 4, 2 ↔ 3): yellow goes to the top-right corner, blue to row 2 column 2, the red half-square to the bottom-left cell with its right angle in the bottom-RIGHT corner, and the dots to the top-left cell and row 4 column 3: (d). (b) moves the red half-square without flipping it, (a) swaps top and bottom, and (c) does both.