The correct answer is "turn when there is no approaching traffic."
When making a turn at an intersection where there are two or more lanes in each direction, you must turn when there is no approaching traffic.
Good driving implies knowing the meaning of traffic signals, lights and being cautious every time you drive.
When you approach an intersection you stop to watch both sides of the street. It could be a one-way street or a two-way street. That is why you must check twice to both sides of the road and confirm that no vehicles are approaching, and then proceed.
