What must you anticipate in this situation?

Your answer is correct because the blue car ahead is positioned in a lane going straight, so according to German traffic rules, it is expected to continue driving straight through the intersection. The red bus is currently stopped at a bus stop, and although it may begin to move later, immediate movement is not guaranteed, so you must not assume it will start moving right away. Pedestrians waiting at a bus stop typically remain on the sidewalk until it is safe and they have the right of way to cross; therefore, you should not expect them to step into the road immediately. Anticipating that the blue car will proceed straight allows you to predict the traffic flow correctly and respond appropriately.