On each dial (marks every $30^{\circ }$, long mark at the top) the orange hand turns by the same angle each step. Which dial comes next?

The marks are $30^{\circ }$ apart. The hand starts at the top, then stops halfway between the 2nd and 3rd marks $(75^{\circ })$, then at $150^{\circ }$ and $225^{\circ }$: it turns $75^{\circ }$ clockwise each time. The next position is $225^{\circ }+75^{\circ }=300^{\circ }$, exactly on the 10th mark: (c). (b) turns only $60^{\circ }$, (d) turns $90^{\circ }$ and (a) turns back anticlockwise.