The "correct" answer is the 0->180 car has no indicator on as it enters the roundabout, and has its right indicator on as it exits the roundabout.

The 90->270 car sees the right indicator and lets the other car passed.

The real answer is somewhere between the above and the 90->270 car waiting to enter the roundabout because it is not sure if the other car is actually going 0->180 or 0->270 because they are a shit diver that doesn't indicate on roundabouts.