C. Only if the red bus is parked in a bus stop
You shouldn't block vehicles trying to exit a side road, so before you pull up in a line of traffic, check to your right and left that there aren't roads entering the main carriageway where traffic might want to exit, or traffic from the main carriageway might want to turn into.
In the case of vehicle C, the motorbike, there is enough room for it to pull up behind the green car and still leave the red box free. For vehicle A, it doesn't have enough room and would block the exit. Vehicle B also doesn't have much room.
Blocking the exit doesn't only stop vehicles from pulling out, but it means that vehicles turning in from the other carriageway have to stop and that stops the traffic flow on the other side of the road (assuming there isn't a median strip).