What does Zimbabwean law require regarding seatbelt usage in motor vehicles equipped with them?

1. The driver and all passengers in seats fitted with seatbelts must wear them at all times while the vehicle is in motion
2. Only the driver is legally required to wear a seatbelt
3. Seatbelts are optional when driving at speeds below 60 km/h in urban areas
4. Seatbelts are only mandatory for passengers under 18 years of age