Two shaded cells travel round the outer ring of a four-by-four board: the orange one clockwise and the blue one anticlockwise. Which board comes next?

The orange cell moves 1, 2, 3 cells clockwise, so next it moves 4 cells: from the bottom-right corner to the left end of the third row. The blue cell always moves 2 cells anticlockwise, from the top of the board's second column down to the second cell of the left edge: (c). (a) moves orange only 3 cells, (b) leaves blue where it was and (d) moves orange five cells.