How do the Road Traffic (Construction, Equipment and Use) Regulations, 2015 define the period 'at night', during which Zimbabwe's vehicle lighting duties apply?

1. From half past five in the afternoon (17:30) until half past six the following morning (06:30)
2. From 9:00 p.m. until 5:00 a.m. the following morning
3. From the moment the sun sets until the moment it rises, as observed by the driver
4. From midnight until 4:00 a.m., and only where there is no street lighting