This square pattern looks exactly the same after every quarter turn about its centre. Which answer figure fills the missing quarter?

Going clockwise, each quarter is the previous one turned $90^{\circ }$ clockwise about the centre: top-left $\to$ top-right $\to$ bottom-right $\to$ bottom-left. Turning the bottom-right quarter one more quarter turn clockwise (the same as turning the top-left quarter a quarter turn anticlockwise) lays the orange blade along the left half of the centre line, hanging downwards: (d). (a) is a mirror image, which would be right for a pattern with mirror lines, and (b) and (c) copy a quarter without turning it.