At an intersection controlled by a standard circular (non-arrow) traffic signal light, what are the rules regarding turning right when the circular light is steady red (圆屏红灯)?

1. Right turns are strictly prohibited under all circumstances during a red light
2. Vehicles may turn right only if accompanied by an emergency horn honk
3. Vehicles must wait until the circular light turns green before initiating a right turn
4. Vehicles may turn right without impeding the movement of passing vehicles and pedestrians, provided no red right-turn arrow light or prohibitory sign is present