Two flags change at every step: the orange flag turns about its centre and the blue flag is flipped upside down. Which figure comes next?

The orange flag turns a quarter turn clockwise each step (upright, lying right, upside down, lying left), so next it is upright again. The blue flag is turned upside down at every step, so it alternates between upright and upside down; next it is upright: (b). (a) leaves the blue flag upside down, and (c) and (d) turn the orange flag by the wrong amount.