The arrow turns at every step, but two different turns take turns with each other. Which figure comes next?

The turns go: a quarter turn clockwise (up to right), a half turn (right to left), a quarter turn clockwise (left to up), a half turn (up to down). The next step is a quarter turn clockwise again: from down to left: (b). (c) repeats the half turn, (a) turns a quarter turn the wrong way and (d) does not turn.