Two different series are mixed together here: the boxes in odd places form one series and the boxes in even places form another. Which figure goes in the last box?

Boxes 1, 3 and 5 show an arrow turning $90^{\circ }$ clockwise each time. Boxes 2 and 4 follow the same rule: the whole square turns $90^{\circ }$ clockwise, so the orange quarter goes top-left $\to$ top-right and the dot bottom-left $\to$ top-left. Box 6 is box 4 turned once more: orange quarter bottom-right, dot top-right: (b). (a) repeats box 2, (c) is a half turn of box 4 and (d) moves only the orange quarter.