Yes, because it improves the effectiveness of the airbag: Correct
Even though a vehicle is equipped with airbags, wearing a seat belt is still necessary and improves the overall safety. The seat belt works in conjunction with the airbag to secure the occupant in place during a crash, preventing them from being thrown forward and reducing the risk of injury. The airbag alone cannot provide sufficient protection without the seat belt, as it is designed to protect the upper body but not keep the occupant from moving around in the seat.
It is recommended, but not necessary: This is incorrect because wearing a seat belt is legally required in most places, even in vehicles with airbags. It is not just recommended but mandatory for safety.
No, if the airbags are activated, it is not necessary: This is incorrect because airbags cannot function as the only means of protection. While airbags help cushion the impact, the seat belt ensures that the occupant remains in the correct position, reducing the likelihood of injury.