Watch the two hands separately. The orange hand turns further at every step; the dark hand turns steadily. Which dial comes next in the series?

The orange hand turns clockwise by $45^{\circ },90^{\circ },135^{\circ },180^{\circ }$, so next by $225^{\circ }$: from pointing right to pointing up-left. The dark hand turns $90^{\circ }$ anticlockwise each time, from right to up: (d). (a) turns the orange hand anticlockwise, (b) repeats $180^{\circ }$ and (c) leaves the dark hand still.