B is made from A by a turn and a change of shading. Do the same to C. Which answer is right?

From A to B the board makes half a turn (the orange quarter goes from top-left to bottom-right, the circle from bottom-right to top-left, and the upward arrow drops to the bottom-left pointing down) and orange and white swap. Half a turn of C puts the two orange quarters on the left and the triangles on the right pointing down and left, then swapping colours makes the quarters white, the down-pointing triangle orange and the left-pointing one white: (c). (a) skips the colour swap and (b) mirrors instead of turning.