At an intersection without traffic signals, two vehicles approaching from opposite directions enter the same lane: Vehicle A is turning right, and Vehicle B is turning left. According to traffic rules, who must yield (右转让左转)?

1. Vehicle B (turning left) must yield to Vehicle A (turning right)
2. Both vehicles may proceed simultaneously without yielding
3. The vehicle that sounded its horn first has priority
4. Vehicle A (turning right) must yield to Vehicle B (turning left)