Each figure should be the previous one turned through the same angle anticlockwise. Find the figure that does not fit.

From (a) the figure turns $135^{\circ }$ anticlockwise each step, so the triangle goes from the right to the upper-left, then down, then up-right, then left. Figure (b) is turned $135^{\circ }$ clockwise instead, putting the triangle at the lower-left, so (b) is wrong. Check: (c) is (a) turned $270^{\circ }$ anticlockwise.